# Adaptive User Profiling in E-Commerce and Administration of Public Services
## 2 Related Work
### Profile Structure
#### 2.2.2 Data Collection  
After having created a user profile, the next step is to collect information about the user so that it can eventually be analyzed. There are several ways to collect information about users, with some of them discussed below [15]. The easiest and quickest way to collect information is through direct user interaction with the system, where the latter is asked to answer a series of questions that will help the system \"learn\" about him/her. This process usually takes place during registration with the system, at which point the user is asked to fill in forms or other interfaces that serve this purpose. Usually, this is an optional type of intelligence as users may not be willing to fill out lengthy forms, and this information rarely changes over time. In general, this information is comprised of demographic details, such as the user's age, marital status or sex. However, there are several problems with collecting information in the first way, as users may not want to provide much data, and this has led to the creation of a second way which learns the user's preferences by observing the user interacting with the system. In this case, the system does not automatically request information about preferences from the user. Instead, it comes as the user navigates through the system and is subconsciously asked to make some decisions. Thus, the system learns dynamically from observing their interactions. For this reason, for the system to learn about a profile, the user's behavior should be repetitive, i.e., the user's actions should be performed under similar conditions at different points in time. There is also a third hybrid mode which is a combination of the two above [16; 17]. That is, data are collected not only by asking the user to answer questions directly, but also during the user's interaction with the system. This mode combines the advantages of the two previous ones, thus making it ideal for most profiling systems. Each method has its advantages and disadvantages. The first method is usually the best when data need to be collected quickly, but there are several problems. First, it lacks the ability to adapt to changes and user preferences. Secondly, it is highly dependent on the user's willingness to provide the information and it is likely to become invalid after a period of time. Third, users may not write true information on the forms and those who are willing to provide true information may not know how to express their interests. However, users have full control over the information collected and it is their decision what they want to share with the system. In the second method, the information is gathered by observing the user's movements in the system, so it takes more time to gather information, and this information cannot be changed or seen by the users. Moreover, if there is no repetition in the user's actions, the pattern cannot be discovered. However, this information can be easily and automatically changed so that the system is always aware of and more accurate regarding the user's preferences. This could be a simple case of using cookies to store and track visits from particular users, including the pages and products viewed, or it could be something more advanced such as eye movements, or even motion detection [18]. Cookies could be used to save some basic information and preferences about users, such as their individual login information or favorite sports or politics. They could also be used for personalization issues. As customers are browsing in e-shops and viewing certain items or parts of a site, cookies could be used to help build targeted ads. Finally, cookies could be used to track items users previously viewed, allowing the e-shop sites to suggest similar goods they might like and keep items in shopping carts for future reference. However, we must keep in mind that cookies have some negative aspects as well. Many users regularly delete cookies from their browsers. Others will not allow cookies to be stored on their machines for security reasons.