Patent Publication Number: US-11049146-B1

Title: Discount offer with time period defined by user impression

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of co-pending U.S. application Ser. No. 15/433,895, filed Feb. 15, 2017, which is incorporated by reference in its entirety. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to providing discount offers on an online system, and more specifically to providing an offer for a discount that becomes valid at the time it is displayed to a user. 
     BACKGROUND 
     Many online systems display content from third-party merchants alongside content that was generated on the online system. Displaying merchant content on an online system gives rise to several benefits for the merchants, the users of the online system, and the online system itself. For instance, it gives a merchant a platform to promote itself or its products and possibly increase its sales as a result, it provides an additional source of content that users of the online system may find interesting, and it may provide a revenue stream for the online system. 
     SUMMARY 
     An online system receives discount offers from merchants and displays those discount offers to users. A discount offer is a content item provided by a merchant that offers a user a discount that is valid for a limited time period. The user can redeem the discount by completing a purchase with the merchant while the discount is valid. Because a discount offer presents the user with an opportunity to save money on a purchase with the merchant, a discount offer gives the user a stronger incentive to view products that can be purchased from the merchant and to follow through with a purchase. 
     Some of the discount offers are variable-start discount offers, which provide for a discount that becomes valid when the discount offer is displayed to the user and remains valid for a certain length of time (the offer duration). To implement these variable-start discount offers, a timestamp representing the time at which the variable-start discount offer is displayed is recorded, and the recorded timestamp is encoded into an encoded timestamp. The encoded timestamp is provided to the merchant system when the user makes a purchase. For example, the encoded timestamp may be a discount code with the timestamp encoded into it, or a digitally signed URL which has the timestamp encoded into it and which points to the merchant&#39;s website. The merchant extracts the recorded timestamp from the encoded timestamp and compares the recorded timestamp to the time of the purchase. If the time elapsed between the timestamp and the purchase is less than the offer duration, then the merchant system applies the discount to the purchase. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram of a system environment in which an online system operates, in accordance with an embodiment of the invention. 
         FIG. 2A  is a block diagram of an online system, in accordance with an embodiment of the invention. 
         FIG. 2B  is an illustration of a first type of discount offer, in accordance with an embodiment of the invention. 
         FIG. 2C  is an illustration of a second type of discount offer, in accordance with an embodiment of the invention. 
         FIG. 3  is an interaction diagram illustrating a method for sending a user a notification of a pre-announced discount offer, in accordance with an embodiment of the invention. 
         FIG. 4  is an interaction diagram illustrating a method for providing a variable-start discount offer with a start time defined by a user impression, in accordance with an embodiment of the invention. 
     
    
    
     The figures depict various embodiments of the present invention for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the invention described herein. 
     DETAILED DESCRIPTION 
     Ordinarily, merchant content that is displayed on an online system simply includes graphics or text promoting the merchant. Conventional merchant content provides no opportunities for users to engage with the merchant and often fails to provide a compelling reason for a user to purchase something with the merchant. As a result, many users simply scroll past merchant content without paying much attention to it when it is displayed to them by the online system. 
     System Architecture 
       FIG. 1  is a high level block diagram of a system environment  100  for an online system  140 . The system environment  100  shown by  FIG. 1  comprises one or more client devices  110 , a network  120 , one or more merchant systems  130 , and the online system  140 . In alternative configurations, different and/or additional components may be included in the system environment  100 . 
     The client devices  110  are one or more computing devices capable of receiving user input as well as transmitting and/or receiving data via the network  120 . In one embodiment, a client device  110  is a conventional computer system, such as a desktop or laptop computer. Alternatively, a client device  110  may be a device having computer functionality, such as a personal digital assistant (PDA), a mobile telephone, a smartphone or another suitable device. A client device  110  is configured to communicate via the network  120 . In one embodiment, a client device  110  executes an application allowing a user of the client device  110  to interact with the online system  140 . For example, a client device  110  executes a browser application to enable interaction between the client device  110  and the online system  140  via the network  120 . In another embodiment, a client device  110  interacts with the online system  140  through an application programming interface (API) running on a native operating system of the client device  110 , such as IOS® or ANDROID™. 
     The client devices  110  are configured to communicate via the network  120 , which may comprise any combination of local area and/or wide area networks, using both wired and/or wireless communication systems. In one embodiment, the network  120  uses standard communications technologies and/or protocols. For example, the network  120  includes communication links using technologies such as Ethernet, 802.11, worldwide interoperability for microwave access (WiMAX), 3G, 4G, LTE, code division multiple access (CDMA), digital subscriber line (DSL), etc. Examples of networking protocols used for communicating via the network  120  include multiprotocol label switching (MPLS), transmission control protocol/Internet protocol (TCP/IP), hypertext transport protocol (HTTP), simple mail transfer protocol (SMTP), and file transfer protocol (FTP). Data exchanged over the network  120  may be represented using any suitable format, such as hypertext markup language (HTML) or extensible markup language (XML). In some embodiments, all or some of the communication links of the network  120  may be encrypted using any suitable technique or techniques. 
     One or more merchant systems  130  may be coupled to the network  120  for communicating with the client devices  110  and the online system  140 , which is further described below in conjunction with  FIG. 2A . In one embodiment, a merchant system  130  is a system that facilitates online purchases. For instance, the merchant system  130  performs tasks such as providing a website (or a dedicated application executing on a client device  110 ) that displays products for sale and provides an interface for purchasing those products online, tracking inventory for products, and generating discount offers that allow customers to redeem discounts on purchases made through the merchant system  130 . As referred to herein, the products that can be purchased through a merchant system  130  can include any sort of goods or services, including physical goods (e.g., clothing, shoes, electronics), digital goods (e.g., downloadable software applications, application-specific purchases such as in-game currency or access to paid features in an otherwise free application), subscriptions (e.g., magazines and newspapers, access to subscription-based electronic services such as NETFLIX, AMAZON PRIME, and XBOX LIVE), and real-world services (e.g., music lessons, ridesharing services such as LYFT and LIBER). 
       FIG. 2A  is an example block diagram of an architecture of the online system  140 . The online system  140  shown in  FIG. 2A  includes a user profile store  205 , a content store  210 , an action logger  215 , an action log  220 , an edge store  225 , a discount offer module  230 , and a web server  240 . In other embodiments, the online system  140  may include additional, fewer, or different components for various applications. Conventional components such as network interfaces, security functions, load balancers, failover servers, management and network operations consoles, and the like are not shown so as to not obscure the details of the system architecture. 
     Each user of the online system  140  is associated with a user profile, which is stored in the user profile store  205 . A user profile includes declarative information about the user that was explicitly shared by the user and may also include profile information inferred by the online system  140 . In one embodiment, a user profile includes multiple data fields, each describing one or more attributes of the corresponding user of the online system  140 . Examples of information stored in a user profile include biographic, demographic, and other types of descriptive information, such as work experience, educational history, gender, hobbies or preferences, location and the like. A user profile may also store other information provided by the user, for example, images or videos. In certain embodiments, images of users may be tagged with identification information of users of the online system  140  displayed in an image. A user profile in the user profile store  205  may also maintain references to actions by the corresponding user performed on content items in the content store  210  and stored in the action log  220 . 
     While user profiles in the user profile store  205  are frequently associated with individuals, allowing individuals to interact with each other via the online system  140 , user profiles may also be stored for entities such as businesses or organizations. This allows an entity to establish a presence on the online system  140  for connecting and exchanging content with other online system users. The entity may post information about itself, about its products or provide other information to users of the online system using a brand page associated with the entity&#39;s user profile. Other users of the online system may connect to the brand page to receive information posted to the brand page or to receive information from the brand page. A user profile associated with the brand page may include information about the entity itself, providing users with background or informational data about the entity. 
     The content store  210  stores objects that each represent various types of content. Examples of content represented by an object include a page post, a status update, a photograph, a video, a link, a shared content item, a gaming application achievement, a check-in event at a local business, a brand page, or any other type of content. Online system users may create objects stored by the content store  210 , such as status updates, photos tagged by users to be associated with other objects in the online system, events, groups or applications. In some embodiments, objects are received from third-party applications or third-party applications separate from the online system  140 . For example, discount offers are received from a merchant system  130  and stored as objects in the content store  210 . In one embodiment, objects in the content store  210  represent single pieces of content, or content “items.” Hence, users of the online system  140  are encouraged to communicate with each other by posting text and content items of various types of media through various communication channels. This increases the amount of interaction of users with each other and increases the frequency with which users interact within the online system  140 . 
     The action logger  215  receives communications about user actions internal to and/or external to the online system  140 , populating the action log  220  with information about user actions. Examples of actions include adding a connection to another user, sending a message to another user, uploading an image, reading a message from another user, viewing content associated with another user, attending an event posted by another user, among others. In addition, a number of actions may involve an object and one or more particular users, so these actions are associated with those users as well and stored in the action log  220 . 
     The action log  220  may be used by the online system  140  to track user actions on the online system  140 , as well as actions on merchant systems  130  that communicate information to the online system  140 . Users may interact with various objects on the online system  140 , and information describing these interactions are stored in the action log  220 . Examples of interactions with objects include: commenting on posts, sharing links, and checking-in to physical locations via a mobile device, accessing content items, and any other interactions. Additional examples of interactions with objects on the online system  140  that are included in the action log  220  include: commenting on a photo album, communicating with a user, establishing a connection with an object, joining an event to a calendar, joining a group, creating an event, authorizing an application, using an application, expressing a preference for an object (“liking” the object) and engaging in a transaction. Additionally, the action log  220  may record a user&#39;s interactions with advertisements on the online system  140  as well as with other applications operating on the online system  140 . In some embodiments, data from the action log  220  is used to infer interests or preferences of a user, augmenting the interests included in the user&#39;s user profile and allowing a more complete understanding of user preferences. 
     The action log  220  may also store user actions taken on a merchant system  130 , such as an external website, and communicated to the online system  140 . For example, an e-commerce website that primarily sells sporting equipment at bargain prices may recognize a user of an online system  140  through a social plug-in enabling the e-commerce website to identify the user of the online system  140 . Because users of the online system  140  are uniquely identifiable, e-commerce websites, such as this sporting equipment retailer, may communicate information about a user&#39;s actions outside of the online system  140  to the online system  140  for association with the user. Hence, the action log  220  may record information about actions users perform on a merchant system  130 , including webpage viewing histories, advertisements that were engaged, purchases made, and other patterns from shopping and buying. 
     In one embodiment, an edge store  225  stores information describing connections between users and other objects on the online system  140  as edges. Some edges may be defined by users, allowing users to specify their relationships with other users. For example, users may generate edges with other users that parallel the users&#39; real-life relationships, such as friends, co-workers, partners, and so forth. Other edges are generated when users interact with objects in the online system  140 , such as expressing interest in a page on the online system, sharing a link with other users of the online system, and commenting on posts made by other users of the online system. Users and objects within the online system can represented as nodes in a social graph that are connected by edges stored in the edge store. 
     In one embodiment, an edge may include various features each representing characteristics of interactions between users, interactions between users and object, or interactions between objects. For example, features included in an edge describe rate of interaction between two users, how recently two users have interacted with each other, the rate or amount of information retrieved by one user about an object, or the number and types of comments posted by a user about an object. The features may also represent information describing a particular object or user. For example, a feature may represent the level of interest that a user has in a particular topic, the rate at which the user logs into the online system  140 , or information describing demographic information about a user. Each feature may be associated with a source object or user, a target object or user, and a feature value. A feature may be specified as an expression based on values describing the source object or user, the target object or user, or interactions between the source object or user and target object or user; hence, an edge may be represented as one or more feature expressions. 
     The edge store  225  also stores information about edges, such as affinity scores for objects, interests, and other users. Affinity scores, or “affinities,” may be computed by the online system  140  over time to approximate a user&#39;s affinity for an object, interest, and other users in the online system  140  based on the actions performed by the user. A user&#39;s affinity may be computed by the online system  140  over time to approximate a user&#39;s affinity for an object, interest, and other users in the online system  140  based on the actions performed by the user. Computation of affinity is further described in U.S. patent application Ser. No. 12/978,265, filed on Dec. 23, 2010, U.S. patent application Ser. No. 13/690,254, filed on Nov. 30, 2012, U.S. patent application Ser. No. 13/689,969, filed on Nov. 30, 2012, and U.S. patent application Ser. No. 13/690,088, filed on Nov. 30, 2012, each of which is hereby incorporated by reference in its entirety. Multiple interactions between a user and a specific object may be stored as a single edge in the edge store  225 , in one embodiment. Alternatively, each interaction between a user and a specific object is stored as a separate edge. In some embodiments, connections between users may be stored in the user profile store  205 , or the user profile store  205  may access the edge store  225  to determine connections between users. 
     The discount offer module  230  performs a variety of operations to manage discount offers. As referred to herein, a discount offer is a type of content item provided by a merchant that offers the user a discount that is valid for a limited time period. If a user makes a purchase from the merchant while the discount is valid, then the merchant applies the discount to the user&#39;s purchase. For example, an offer may give a user an opportunity to receive a 20% discount on the purchase of a new suit at a clothing retailer if the purchase is made during a particular long weekend. The discount offer module  230  receives discount offers from one or more merchant systems  130  and stores the discount offers as content items in the content store  210 . When users access the online system  140 , the module  230  selects discount offers to be displayed to users and sends the selected discount offers to those users for display on the users&#39; client devices  110 . 
     The discount offer module  230  may provide two different types of discount offers. Referring now to  FIG. 2B , an example of a first type of discount offer is shown. The first type of discount offer is a fixed-start discount offer, which provides a discount that becomes valid at a fixed start time. In one embodiment, a fixed-start discount offer includes an offer start time and an offer end time, and the discount is valid between the offer start time and the offer end time. For example, a fixed-start discount offer shown in  FIG. 2B  provides a 20% discount on men&#39;s suits  252 , and the offer states that the discount is valid from 4:00 PM to 7:00 PM on the day it is being displayed  254 . In another embodiment, a fixed-start discount offer includes an offer start time and an offer duration, and the discount becomes valid at the offer start time and remains valid for the offer duration. For example, a fixed-start discount offer provides a discount that becomes valid at 5:30 PM on a particular date and remains valid for the next two hours. In still another embodiment, a fixed-start discount offer provides a discount that becomes valid upon the occurrence of some sort of external triggering event or a fixed period of time after the occurrence of a triggering event (e.g., a discount becomes valid one hour after the end of the Super Bowl) and remains valid for an offer duration. A fixed-start discount offer also includes a discount code, such as the code 20OFFMENSSUITS  256  shown in  FIG. 2B . If provided to the merchant system  130  while the discount is valid, the discount code causes the merchant system  130  to apply the discount to a purchase. 
     After a discount offer is displayed to a user, the user can interact with the discount offer in a variety of ways. For example, the discount offer includes a uniform resource locator (URL) for the merchant website where the offer can be redeemed. Thus, if the discount offer is displayed to the user while the discount is valid, the user can select the URL (e.g., by selecting a “USE OFFER” button  258  displayed as part of the discount offer, as shown in  FIG. 2B , or by selecting a promotional graphic displayed with the offer, such as the graphic of two suits  260  shown in  FIG. 2B ) to easily view the merchant&#39;s website, make a purchase from the merchant, and redeem the discount. In one embodiment, the discount offer  230  also provides users with an option to save a discount offer for later. In the example shown in  FIG. 2B , a “save for later” button  262  is displayed as part of the discount offer. If the user selects the “save offer” button, the module  230  creates an edge connecting the user&#39;s profile with the content object representing the discount offer and stores the edge in the edge store  225 . The user can later navigate to a “saved offers” interface provided by the online system  140  to view discount offers that the user has previously saved. 
     In some embodiments, the discount offer module  230  sends notifications about discount offers upon detecting that certain events have occurred. For example, a discount offer for a purchase from a particular merchant is displayed to a user before the offer becomes valid. If the discount offer module  230  detects that the user has viewed a web page operated by the same merchant after the discount offer was displayed to the user, then the module  230  may send a notification about the discount offer to the user. Sending a notification in this manner is beneficial because it has the effect of reminding the user about the discount offer after the user has already expressed an interest in the merchant by visiting the merchant&#39;s website. As another example, if a discount offer is first displayed to a user when the user is accessing the online system  140  on a smartphone or other mobile device (i.e., a device running a mobile operating system), the module  230  may send a notification about the discount offer after detecting that the user has begun interacting with the online system  140  on a conventional computer system, such as desktop or laptop computer. This is advantageous because some users may prefer to conduct online commerce activities on a desktop or laptop computer (e.g., because such computers include a larger display that allows the user to view several products at once). As still another example, the user saves a discount offer for later, and the discount offer module  230  sends the user a notification at a fixed time before the discount becomes invalid (e.g., 30 minutes before the discount becomes invalid) to remind the user that the discount is about to expire. 
     Referring now to  FIG. 2C , a second type of discount offer is shown. The second type of discount offer is a variable-start discount offer, which provides a discount that becomes valid for a particular user as soon as the discount offer is displayed to the user and that remains valid for a fixed time period. A variable-start discount offer includes an offer duration. For example, the variable-start discount offer shown in  FIG. 2C  provides a similar 20% discount off men&#39;s suits  272 , but the discount shown in  FIG. 2C  becomes valid once it is displayed and remains valid for the following three hours. The discount offer shown in  FIG. 2C  was displayed on the user&#39;s client device  110  at 4:36 PM, so it contains a statement  274  informing the user that it will be valid until 7:36 PM. Similar to a fixed-start discount offer, a variable-start discount offer also includes a URL (which can be selected by selecting the “use offer” button  278  or the promotional graphic  280  displayed with the discount offer) and a “save for later” button  282  that allows the user to save the discount offer for later. 
     When the module  230  selects a variable-start discount offer to be displayed to a user, the module  230  records a timestamp representing the date and time at which the discount offer becomes valid. The module  230  encodes the timestamp to generate an encoded timestamp and provides the encoded timestamp for delivery to the merchant system  130  (e.g., by sending the encoded timestamp to the user, who in turn provides the encoded timestamp to the merchant system  130  when making a purchase, or by sending the encoded timestamp directly to the merchant system  130 ). In one embodiment, the encoded timestamp is a user-specific discount code that has the timestamp encoded into it. For example, the user-specific discount code  276  shown in  FIG. 2C  has encoded into it a timestamp indicating that the offer becomes valid at 4:36 PM on Oct. 31, 2016. By encoding the timestamp into a user-specific discount code in this manner, the merchant system  130  can determine the amount of time that has elapsed between the timestamp and the time at which the purchase is being made. The merchant system  130  can then compare the elapsed time to the offer duration to determine whether the purchase is being made while the discount is still valid. 
     Referring back to  FIG. 2A , the web server  240  links the online system  140  via the network  120  to the one or more client devices  110 , as well as to the one or more merchant systems  130 . The web server  140  serves web pages, as well as other web-related content, such as JAVA®, FLASH®, XML and so forth. The web server  240  may receive and route messages between the online system  140  and the client device  110 , for example, instant messages, queued messages (e.g., email), text messages, short message service (SMS) messages, or messages sent using any other suitable messaging technique. A user may send a request to the web server  240  to upload information (e.g., images or videos) that are stored in the content store  210 . Additionally, the web server  240  may provide application programming interface (API) functionality to send data directly to native client device operating systems, such as IOS®, ANDROID™, WEBOS® or RIM®. 
     Sending Notifications of Pre-Announced Discount Offers 
       FIG. 3  is an interaction diagram illustrating a method for sending a user a notification of a pre-announced discount offer. In other embodiments, the method may include different and/or additional steps than those shown in  FIG. 3 . Additionally, steps of the method may be performed in different orders than the order described in conjunction with  FIG. 3  in various embodiments. 
     As referred to herein, a pre-announced discount offer is a fixed-start discount offer that the discount offer module  230  begins displaying to users of the online system  140  before the discount offer&#39;s start time. Thus, the discount offer is “pre-announced” because users are shown an offer for a discount that is currently invalid but will become valid in the future. 
     The merchant system  130  sends  302  a pre-announced discount offer to the online system  140 , and the discount offer module  230  stores the pre-announced discount offer in the content store  210 . Because a pre-announced discount offer is a type of fixed-start offer, the pre-announced offer includes the elements of the fixed-start discount offer that are described above with reference to  FIG. 2B . In particular, a pre-announced discount offer includes an offer start time, an offer end time (or an offer duration), and a discount code. A pre-announced discount offer may also include promotional graphics and text to be displayed with the offer, and it may further include the terms and conditions of the discount being offered, such as the amount of the discount (e.g., a percentage or a dollar amount), the subject matter of the discount (e.g., the discount is for men&#39;s suits), and limitations on the discount (e.g., the discount may not be combined with other discounts or promotions). 
     Prior to the offer start time, the discount offer module  230  selects  304  the pre-announced discount offer for display to a user. The selection  304  of the pre-announced discount offer can be performed in response to the user accessing the online system  140 . For example, when the user logs on to the online system  140  through a web browser application or dedicated application on a client device  110 , the client device  110  automatically requests a certain number of items to populate different portions of the online system&#39;s user interface (e.g., a newsfeed, a sidebar, etc.), and the pre-announced discount offer is selected  304  as one of the items to be displayed in the user interface. 
     The online system  140  sends  306  the pre-announced discount offer to the user&#39;s client device  110 , and the client device  110  displays  308  the pre-announced discount offer to the user. Because the pre-announced discount offer is displayed to the user before the offer start time, the discount is not yet valid at the time the pre-announced discount offer is displayed. Thus, the user cannot yet use the discount. For example, the pre-announced discount offer is displayed without the discount code  256  shown in  FIG. 2B . Alternatively, the pre-announced discount offer is displayed with the discount code  256 , but the merchant system  130  does not allow the discount code to be redeemed before the discount becomes valid. As another example, the pre-announced discount offer is displayed to the user without the “use offer” button  258  shown in  FIG. 2B . In these examples, the “save for later” button  262  may still be displayed. If the user selects the option to save  309 A the pre-announced discount offer for later, the client device  110  sends  309 B a request to the online system  140  to save the pre-announced discount offer for later. In response to receiving the request, the discount offer module  230  creates  309 C an edge between the user&#39;s profile and the content item representing the pre-announced discount offer. 
     After the discount offer is displayed  308  to the user, the discount offer module  230  can send  316  the user a notification about the offer after the module  230  detects a triggering condition. The notification has the function of reminding the user about the pre-announced discount offer. In one embodiment, the discount offer module  230  only sends notifications for pre-announced discount offers that the user has saved (i.e., pre-announced discount offers that are connected to the user&#39;s profile via an edge). In another embodiment, the discount offer module  230  can send notifications for any pre-announced discount offer that has previously been displayed to the user, regardless of whether the user saved the pre-announced discount offer. 
     Steps  310 ,  312 , and  314  of  FIG. 3  illustrate one example of a triggering condition. Specifically, these steps  310 ,  312 ,  314  illustrate a triggering condition that causes the discount offer module  230  to send a notification upon detecting that the user has viewed a web page provided by the merchant system. At some point after the client device  110  displays  308  the discount offer to the user, the user uses the client device  110  (or another client device  110  associated with the user) to view a web page provided by the merchant system  130 , and this causes the client device  110  to retrieve  310  the web page. For example, the user visits the merchant&#39;s website to view products offered by the merchant or to view other information about the merchant. 
     The merchant web page is configured so that displaying the merchant web page on a client device  110  causes the client device  110  to send  312  an indication to the online system  140  that the user has viewed the merchant web page. For example, the merchant web page contains a web beacon or tracking pixel (also known as a page tag, pixel tag, or clear GIF) for the online system  140 , and when a web browser application on the client device  110  displays the web page, the web beacon causes the web browser application to request data from the online system  140 . In one embodiment, the request identifies the user, which allows the online system  140  to determine that the user has viewed the merchant web page. 
     After the discount offer module  230  determines  314  that the discount has become valid (e.g., the offer start time has passed), the module  230  sends  316  a notification to the client device  110  to remind the user of the pre-announced discount offer, and the client device  110  displays  318  the notification to the user. In one embodiment, the notification includes the identity of the merchant. For example, the notification may inform the user that, “An offer from Men&#39;s Clothing Superstore is valid right now!” The notification may also include other information about the discount, such as the offer end time, the amount of time remaining before the discount becomes invalid, the amount of the discount, and the subject matter of the discount. In still another embodiment, the notification simply states that the user has a pre-announced discount offer that is currently valid without any other information about the discount. 
     Although the interaction diagram shown in  FIG. 3  indicates that the user retrieves  312  and views the merchant web page before the discount becomes valid  314 , the timing of these two events as shown in  FIG. 3  is merely exemplary. In another embodiment, the user may additionally or alternatively view the merchant web page after the discount becomes valid, and the discount offer module  230  may still send  316  the notification as long as the discount is still valid at the time the notification is sent. In still another embodiment, the discount offer module  230  may send the notification  316  after receiving the indication but before determining  314  that the discount has become valid. 
     In some embodiments, the discount offer module  230  enforces a minimum time delay between the time at which the online system  140  receives  312  the indication that the user viewed the merchant web page and the time at which the discount offer module  230  sends  316  the notification reminding the user about the merchant&#39;s pre-announced discount offer. For example, the minimum time delay is 30 minutes, so the discount offer module  230  withholds the notification for at least 30 minutes after receiving the indication. 
     Apart from the triggering condition described above, the discount offer module  230  can additionally or alternatively send  316  a notification after one or more other triggering conditions have been satisfied. In some embodiments, the module  230  defines one or more time-based triggering conditions. For example, the module  230  sends  316  the notification a fixed length of time before the offer start time, after the offer start time, or before the offer end time. As another example, the module  230  sends  316  the notification on a weekday after normal working hours (e.g., 9 AM to 5 PM) or on a weekend. In some embodiments, the module  230  defines one or more triggering conditions based on location, network connectivity, or characteristics of the client device  110 . For example, the module  230  sends  316  the notification after determining that the user is at a particular location (e.g., a location corresponding to his or her place of residence), after determining that the user is using a client device  110  with a network connectivity speed faster than a threshold speed or with a network connection of a particular type (e.g., a client device connected via a Wi-Fi connection or an LTE connection), or after determining that the user is using a client device  110  with a display size larger than a threshold display size (e.g., a laptop or desktop computer rather than a mobile device) or a client device  110  with a desktop operating system (e.g., a device running APPLE MACOS or MICROSOFT WINDOWS rather than APPLE IOS or GOOGLE ANDROID). In various embodiments, the online system  140  provides privacy settings that allow the user to enable/disable the use of personal data (e.g., the user&#39;s location, network connectivity speed, and device characteristics) for the operation of these features. 
     This method of providing a notification of a merchant&#39;s currently-valid discount based on a triggering condition is advantageous because it provides the user with a reminder of the discount under conditions that increase the likelihood that the user will claim the discount by making a purchase with the merchant. First, the user has already viewed the pre-announced discount offer at least one time before the time of the notification, so the user is already aware that the discount exists. Second, because the user has viewed the merchant&#39;s website after viewing the pre-announced discount offer, it is likely that the user is at least somewhat interested in claiming the discount. Similarly, other triggering conditions also correspond to conditions that increase the likelihood that the user will claim the discount (e.g., sending the notification after normal working hours, while the user is at home, or while the user is operating a client device with a large screen, a desktop operating system, or a fast network connection). Third, if the notification is sent while the discount is valid, then the notification can inform the user that the user can claim the discount immediately. 
     Providing Discount Offers with Variable-Start Times 
       FIG. 4  is an interaction diagram illustrating a method for providing a variable-start discount offer. In other embodiments, the method may include different and/or additional steps than those shown in  FIG. 4 . Additionally, steps of the method may be performed in different orders than the order described in conjunction with  FIG. 4  in various embodiments. 
     The merchant system  130  sends  402  a variable-start discount offer to the online system  140 , and the discount offer module  230  stores the variable-start discount offer in the content store. As noted above with reference to  FIG. 2C , a variable-start discount offer includes an offer duration, and it offers the user a discount that becomes valid when displayed to the user and remains valid for the offer duration. Similar to a fixed-start discount offer, a variable-start discount offer may also include promotional graphics and text to be displayed with the offer, and it may further include the terms and conditions of the discount being offered, such as the amount of the discount (e.g., a percentage or a dollar amount), the subject matter of the discount (e.g., the discount is for men&#39;s suits), and limitations on the discount (e.g., the discount may not be combined with other discounts or promotions). 
     The discount offer module  230  selects  404  the variable-start discount offer for display to a user. As described above with reference to  FIG. 3 , the selection  404  of the offer can be performed in response to the user accessing the online system  140 , which in turn causes the user&#39;s client device  110  to request one or more items from the online system  140  to populate a user interface of the online system. The module  230  may select the variable-start discount offer as one of the items. 
     The discount offer module  230  records  406  a timestamp representing the time at which the variable-start discount offer is displayed to the user and encodes the recorded timestamp to generate  408  an encoded timestamp. In the embodiment shown in  FIG. 4 , the module  230  records  206  the timestamp in response to the variable-start discount offer being selected  404  for display and before the variable-start discount offer is sent  410  to the client device  110  to be displayed. In this embodiment, it is assumed that the steps of generating  408  the encoded timestamp and sending  410  the variable-start discount offer for display to the user take a relatively small amount of time (e.g., less than a few seconds), so recording the timestamp before these steps  408 ,  410  are performed still yields a sufficiently accurate representation of the time at which the variable-start discount offer is displayed. 
     The encoded timestamp has a format that is capable of being decoded by the merchant system  130  to recreate the recorded, unencoded timestamp. In one embodiment, the encoded timestamp is a user-specific discount code with the timestamp encoded into it. In this embodiment, the user-specific discount code may additionally include other information that would otherwise be included in an ordinary discount code, such as the amount and subject matter of the discount. An example of a user-specific discount code with a timestamp representing 4:36 PM on Oct. 31, 2016 is shown in  FIG. 2C . The example discount code shown in  FIG. 2C  is merely exemplary; in other embodiments, the timestamp is encoded into the user-specific coupon code in a manner that obscures the value of the timestamp, which makes it more difficult for unauthorized third parties to generate user-specific coupon codes in the same format. 
     In another embodiment, the discount offer module  230  generates the encoded timestamp by digitally signing a uniform resource locator (URL) that points to a website provided by the merchant system  130 . In this embodiment, the URL includes a digital signature that allows the merchant system  130  to verify that the URL was generated by the online system  130  and not by an unauthorized third party. The URL additionally includes a representation of the recorded timestamp that the merchant system  130  can extract from the URL. 
     The discount offer module  230  sends  410  both the variable-start discount offer and the encoded timestamp to the client device  110 , and the client device  110  displays  412  the variable-start discount offer in a manner that incorporates the encoded timestamp. For example, if the encoded timestamp is a user-specific discount code, the user-specific discount code may be shown as part of the variable-start discount offer (as shown in the example in  FIG. 2C ). As another example, if the encoded timestamp is a signed URL, the variable-start discount offer may be displayed so that selecting the discount offer&#39;s promotional graphic or the “get offer” button causes the signed URL to be opened in a web browsing window. 
     The variable-start discount offer may be displayed with a message informing the user that the discount is currently valid and becomes invalid after the offer duration has elapsed. For example, the variable-start discount offer is displayed with a message stating, “Valid only for the next three hours,” as shown in the example in  FIG. 2C . To further convey a sense of urgency, the variable-start discount offer may additionally or alternatively be displayed with a countdown timer that displays the time remaining before the discount becomes invalid. 
     In another embodiment, the module  230  sends  410  the variable-start discount offer to the client device before recording  406  the timestamp and generating  408  the encoded timestamp. In this embodiment, the client device  110  displays  412  the variable-start discount offer without incorporating the encoded timestamp. For example, the encoded timestamp is a user-specific discount code. In this example, the variable-start discount offer is displayed without a discount code, but the user can select the “use offer” button to send a request to the online system  140  for an encoded timestamp. In response to receiving the request, the online system records  406  a timestamp, generates  408  an encoded timestamp (i.e., a user-specific discount code), and sends the discount code to the client device  110  so that the client device can display the code as part of the offer. As another example, the encoded timestamp is a digitally signed URL. In this example, selecting the “use offer” button causes the client device  110  to send a request to the online system  140  for an encoded timestamp. In response to receiving the request, the online system  140  performs the same steps of recording  406  a timestamp, generating  408  an encoded timestamp (i.e., a digitally signed URL), and sending the URL to the client device  110 . Upon receiving the URL, the client device  110  opens the URL in a web browsing window. 
     After the variable-start discount offer is displayed  412  to the user, the user uses the client device  110  to make a purchase  414  at the merchant system  130 , and the client device  110  sends the encoded timestamp to the merchant system  130  as part of the process for making the purchase  414 . For example, the encoded timestamp is a user-specific discount code, and the user provides the discount code on a checkout page when making the purchase  414 . As another example, the encoded timestamp is a signed URL, and the merchant system  130  receives information in the signed URL when user uses the signed URL to navigate to the merchant&#39;s website. 
     The merchant system  130  decodes the encoded timestamp to extract the recorded timestamp and determines whether the purchase is being made  414  while the discount is valid. Specifically, the merchant system compares the recorded timestamp to the current time to determine how much time has elapsed between the timestamp (which represents time the offer was displayed) and the present time. Next, the merchant system compares the elapsed time to the offer duration. If the elapsed time is less than the offer duration, then the discount is still valid, and the merchant system  130  applies  416  the discount to the purchase. 
     In an alternative embodiment, the client device  110  records the timestamp locally and sends the recorded timestamp to the online system  140  as part of a request for an encoded timestamp. In response to receiving the request, the online system  140  generates the encoded timestamp and sends the encoded timestamp to the client device  110 . This embodiment is advantageous because recording the timestamp on the client device  110  allows the timestamp to be recorded contemporaneously with the display of the variable-start discount offer, which yields a more accurate representation of the time at which the variable-start discount offer was displayed. In another alternative embodiment, the client  110  records the timestamp and also generates the encoded timestamp. This reduces the communication between the client device  110  and the online system  140  and may allow for less lag between the time the timestamp is recorded and the time the encoded timestamp is available on the client device  110 . 
     In still another alternative embodiment, the online system  140  sends the encoded timestamp directly to the merchant system  130  instead of sending it to the client device  110 . In this embodiment, the online system  140  also sends an identifier for the user so that the merchant system  130  can associate the encoded timestamp with the user to whom the discount offer was displayed. For example, the online system  140  sends a hashed user identifier to the merchant system  130 . 
     In still another alternative embodiment, the online system  140  (or the client device  110 ) records the timestamp and adds the offer duration to the timestamp to determine an end time for the offer (i.e., the time at which the discount becomes invalid). In this embodiment, the offer end time, not the recorded timestamp, is used to generate the encoded timestamp, and the merchant system  130  determines whether the discount is valid at the time of purchase by comparing the purchase time with the offer end time (i.e., the discount is valid if the purchase time is before the offer end time, and the discount is invalid if the purchase time is after the offer end time). 
     In some embodiments, the discount offer module  230  provides a notification to remind the user of the variable-start discount offer if the discount is still valid but the user has not yet redeemed the discount. For example, the module  230  provides a notification about the variable-start discount offer if the user has not redeemed the discount 30 minutes before the discount is set to become invalid. In embodiments where the discount offer module  230  provides the ability to save a variable-start discount offer for later, the discount offer module  230  may provide notifications for variable-start discount offers that the user has saved, but it does not provide notifications for other variable-start discount offers that have been displayed to the user. 
     This method allows an online system to offer a discount that becomes valid at the time it is displayed to a user, which is advantageous because a discount that becomes valid in this manner can convey a stronger sense of urgency to the user, which in turn increases the likelihood that the user will redeem the discount by completing a purchase at the merchant system  130  while the discount is valid. 
     Although this method was only described with reference to a single user, the method can be repeated for many different users of the online system. Because the method provides for a discount that becomes valid at the time the corresponding discount offer is displayed to a particular user, two users who are displayed the same variable-start discount offer at different times would receive discounts that become valid and invalid at different times. In other words, the same variable-start discount offer can be displayed  412  to a second user at a different time, which causes the online system to record  406  a different timestamp and generate  408  a different encoded timestamp. 
     The methods shown in  FIGS. 3 and 4  were described with reference to a discount offer that provides a discount for an online purchase. However, in alternative embodiments, the same methods may also be applied to discount offers that provide a discount for in-person purchases at brick-and-mortar stores. In one embodiment, the merchant system  130  includes a server that communicates over the network  120  with the online system  140  and further includes a network of point-of-sale (POS) systems at one or more brick-and-mortar stores operated by the merchant. In this embodiment, the server sends  302 ,  402  the discount offer to the online system  140 , and one of the POS systems processes the user&#39;s purchase and determines whether a discount should be applied. In addition, the discount code in this embodiment may be a bar code that can be displayed on the screen and scanned by one of the POS systems or a data item that the client device  110  can send to one of the POS systems via a communication technology such as near-field communication (NFC). 
     Pre-announced discount offers for brick-and-mortar stores may be subject to different location-based triggering conditions. In one embodiment, the discount offer module  230  sends  316  a notification about a merchant&#39;s pre-announced discount offer to the user if the online system  140  determines that the user is currently near a location corresponding to a brick-and-mortar store operated by the merchant (e.g., the distance between the user&#39;s location and the store&#39;s location is less than a threshold distance; the user&#39;s location is within a predefined geo-fence surrounding the store&#39;s location). For example, a pre-announced discount offer for a discount at BROOKS BROTHERS is displayed to a user, and the module  230  sends the user a notification about the pre-announced discount offer as the user is walking through a shopping mall containing a BROOKS BROTHERS store. 
     Variable-start discount offers for brick-and mortar stores may selected  404  and sent  410  in embodiments where the online system  140  can determine the location of the user when selecting  404  the variable-start discount offer along with other content items to display to the user. In one embodiment, the online system  140  determines, while selecting content items for display to the user (e.g., when populating the user&#39;s newsfeed), that the user is close to a brick-and-mortar store operated by merchant that has provided a variable-start discount offer (e.g., the distance between the user&#39;s location and the store&#39;s location is less than a threshold distance; the user&#39;s location is within a predefined geo-fence surrounding the store&#39;s location). Upon determining that the user is near the store, the discount offer module  230  selects  404  the variable-start discount offer, records  406  a timestamp, generates  408  an encoded timestamp, and sends  410  the variable-start discount offer and the encoded timestamp  410  to the user&#39;s client device  110 . In this embodiment, the encoded timestamp  410  may be a barcode or data item with the recorded timestamp encoded into it, and the POS system that scans the barcode or receives the data item extracts the recorded timestamp and determines whether the variable-start discount offer is still valid at the time the purchase is made. For example, suppose a user accesses the online system  140  on a smartphone while he or she is in a shopping mall containing a BROOKS BROTHERS store, and the user has adjusted his or her privacy settings in a manner that allows the online system  140  to determine the user&#39;s location when the user accesses the online system  140  (e.g., via a location sensor such as a GPS receiver on the smartphone). In this example, the discount offer module  230  may select  404  and send  410  a variable-start discount offer for BROOKS BROTHERS for display to the user as part of the user&#39;s newsfeed. In addition to the other elements shown in the example in  FIG. 2C , the variable-start discount offer also may be displayed with a map or description of the location of the BROOKS BROTHERS store within the shopping mall. 
     CONCLUSION 
     The foregoing description of the embodiments of the invention has been presented for the purpose of illustration; it is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Persons skilled in the relevant art can appreciate that many modifications and variations are possible in light of the above disclosure. 
     Some portions of this description describe the embodiments of the invention in terms of algorithms and symbolic representations of operations on information. These algorithmic descriptions and representations are commonly used by those skilled in the data processing arts to convey the substance of their work effectively to others skilled in the art. These operations, while described functionally, computationally, or logically, are understood to be implemented by computer programs or equivalent electrical circuits, microcode, or the like. Furthermore, it has also proven convenient at times, to refer to these arrangements of operations as modules, without loss of generality. The described operations and their associated modules may be embodied in software, firmware, hardware, or any combinations thereof. 
     Any of the steps, operations, or processes described herein may be performed or implemented with one or more hardware or software modules, alone or in combination with other devices. In one embodiment, a software module is implemented with a computer program product comprising a computer-readable medium containing computer program code, which can be executed by a computer processor for performing any or all of the steps, operations, or processes described. 
     Embodiments of the invention may also relate to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, and/or it may comprise a general-purpose computing device selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a non-transitory, tangible computer readable storage medium, or any type of media suitable for storing electronic instructions, which may be coupled to a computer system bus. Furthermore, any computing systems referred to in the specification may include a single processor or may be architectures employing multiple processor designs for increased computing capability. 
     Embodiments of the invention may also relate to a product that is produced by a computing process described herein. Such a product may comprise information resulting from a computing process, where the information is stored on a non-transitory, tangible computer readable storage medium and may include any embodiment of a computer program product or other data combination described herein. 
     Finally, the language used in the specification has been principally selected for readability and instructional purposes, and it may not have been selected to delineate or circumscribe the inventive subject matter. It is therefore intended that the scope of the invention be limited not by this detailed description, but rather by any claims that issue on an application based hereon. Accordingly, the disclosure of the embodiments of the invention is intended to be illustrative, but not limiting, of the scope of the invention, which is set forth in the following claims.