During the past 15 years, the development and adoption of new electronic technologies has altered the traditional patterns of communication between Members of Congress and constituents. Many Members now use e-mail, official websites, blogs, Youtube channels, and Facebook pages to communicate with their constituents—technologies that were either non-existent or not widely available 15 years ago. These technologies have arguably served to potentially enhance the ability of Members of Congress to fulfill their representational duties by providing greater opportunities for communication between the Member and individual constituents, supporting the fundamental democratic role of spreading information about public policy and government operations. However, electronic communications have raised some concerns. Existing law and chamber regulations on the use of communication media such as the United States Postal Service have proven difficult to adapt to the new electronic technologies. In addition, electronic media could provide Members with the ability to easily communicate information traditionally sent to the district (or state) with non-constituents or non-U.S. residents. This report examines Member use of one specific new electronic communication medium: Twitter. After providing an overview and background of Twitter, the report analyzes patterns of Member use of Twitter during two one-week periods in July and August 2009. This report is inherently a snapshot in time of a dynamic process. As with any new technology, the number of Members using Twitter and the patterns of use may change rapidly in short periods of time. Thus, the conclusions drawn from this data can not be easily generalized nor can these results be used to predict future behavior. Members of Congress have more choices and options available to communicate with constituents than they did 15 years ago. In addition to traditional modes of communication such as townhall meetings, telephone calls, and postal mail, Members can now reach their constituents via e-mail, websites, tele-townhalls, online videos, social networking sites, and other electronics-based communication applications. The rise of such electronic communication has altered the traditional patterns of communication between Members and constituents. Although virtually all Members continue to use traditional modes of constituent communication, use of new communications technology is increasing. For example, prior to 1995, there was virtually no e-mail traffic between Members and constituents. In 2008, almost 200 million e-mails were sent to the House of Representatives, and a similar number were sent from House computers. Member official websites, blogs, Youtube channels, and Facebook pages—all non-existent several years ago—also receive significant traffic. Conversely, the amount of postal mail sent to Congress has dropped by more than 50% during the same time period. In addition, electronic technology has reduced the marginal cost of constituent communications; unlike postal letters, Members can reach large numbers of constituents for a fixed cost. Member use of electronic communications has raised several concerns. Some of these concerns are similar to those associated with traditional modes of constituent communications, such as the potential electoral advantage that the franking privilege may confer on incumbent Members. Other issues, such as the use of third-party communication software platforms, are unique to the new electronic mediums. In addition, existing law and chamber regulations on the use of communication media, such as the United States Postal Service, have proven difficult to apply directly to the new electronic technologies. Created in 2006 by developer Jack Dorsey as a tool to keep in touch with friends, Twitter is a web-based social networking service that allows users to send and read short messages. Also considered a micro-blogging site, Twitter users send "tweets" of up to 140 characters. These tweets are displayed on an author's Twitter home page and on the pages of people subscribed to his or her RSS feed. Twitter enables individual users to post thoughts on any number of topics or activities. While Twitter use varies, it has been used by individuals and organizations to state opinions, promote events, and announce the release of products and services. Several legislative branch entities actively use Twitter to communicate with interested parties. These include the U.S. Government Accountability Office (GAO), the Library of Congress (LOC), and the Government Printing Office (GPO). In addition, Restaurant Associates, the House's food service vendor, uses Twitter to announce daily specials and events. Posting under the user name "ushrcafes," a typical tweet might look like this: It's Panini Week in Cannon Cafe! Today's featured panini is Chicken Parmesan. Buy a panini and get a free 16oz fountain drink all week! Because of the 140 character limit on tweets, Twitter messages are necessarily short. The brevity of the messages highlights the ease in which tweets can be quickly sent from mobile devices to followers around the world. The rapid transmission of information allows individuals and groups to communicate instantly without limitation of physical distance. Twitter allows individual users to "follow" other Twitter subscribers and read their tweets from the Twitter homepage. Individuals may choose to follow another Twitter account if they are interested in the information provided, are friends with the Twitter account holder, or if they are a "fan" of an activity or place. Following another user's Twitter account allows for almost instant access to his or her tweets. This can be useful if a follower is looking for a featured item or to better understand the activities of the person or group he or she is following. Individuals who "follow" an individual Twitter user can have instant access to tweets through devices such as a Blackberry, iPhone, or other similar mobile, internet-ready devices. This report analyzes the following questions related to Member use of Twitter: What proportion of Members are using Twitter? How often and when are Members using Twitter? How widely are Member tweets being followed? What are Members tweeting about? For two non-successive weeks, July 26-August 1 and August 9-August 16, 2009, Members and Senators who are registered to use Twitter were tracked for their submissions. The website TweetCongress was used to analyze and count all the tweets issued by Representatives and Senators during these two one-week time periods. During the first week of data collection, the House and Senate were in session. During the second week of data collection, the House and Senate were in recess. Several caveats accompany the results presented. First, CRS relies on TweetCongress's identification and aggregation of Member tweets, which claims to be comprehensive, but may not be exhaustive. Second, the analysis treats all Member tweets as structurally identical, because each individual tweet reveals no information about its genesis. In some cases, Members might be personally tweeting, whereas in others they are delegating Twitter responsibilities to their communications staff. CRS draws no distinction between the two. Similarly, some Members use Twitter as a communication medium in their official public capacity as Members, whereas others use Twitter as a communication medium for their campaign. Although there are important differences in the laws and chamber rules governing these two uses, CRS draws no distinction between the two in its analysis. Third, these results cannot be used to predict future behavior. Finally, the analysis covers only two weeks of Member tweeting. Therefore, it is inherently a snapshot in time of a dynamic process. As with any new technology, the number of Members using Twitter and the patterns of use may change rapidly in short periods of time. Thus, the conclusions drawn from this data can not be easily generalized. As of August 16, 2009, a total of 158 Members of Congress were registered with Twitter, 31 Senators and 127 Representatives. Although more than 80% of those registered are Representatives, registration rates of each chamber are approximately equal in the House (29%) and the Senate (31%). Figure 1 presents the chamber and party affiliation of the 158 registered Members. As shown in Figure 1 , more than half (54%) of the Members registered with Twitter are Republican Members of the House of Representatives. Overall, 64% of registered Members are Republican and 36% are Democrats. In addition to the registration data in Figure 1 , by collecting data for time periods where both the House and the Senate were in session and out of session (in recess), patterns emerged suggesting consistent Twitter usage by Republicans and Democrats regardless of chamber. Figure 2 shows the number of tweets sent by party and chamber affiliation. House Republicans, who constitute 54% of Members registered with Twitter, sent approximately 74% of all tweets during session and approximately 64% of tweets during recess. This is in contrast to House Democrats, who sent 13% of total tweets in session and 16% during recess. Overall, the data also suggest that Senators tweeted less than House Members. In session, Senate Republicans (7%) and Democrats (6%) tweeted almost equally. Although the percentage of Senators tweeting increased during recess (11% for Republicans and 9% for Democrats), the overall usage remained consistent. During the two non-consecutive weeks of observation, Members sent a total of 1,187 tweets, for an average of almost 85 Member tweets per day. Just over 60% of tweets (715) were sent during the first week of observation, when both the House and Senate were in session; just under 40% of tweets (472) were sent during the second week of observation, when both the House and Senate were out of session. Figure 3 reports the number of tweets sent by Members during each day of the week of the observation period. As shown in Figure 3 , Member tweeting during recess was relatively uniform; no day had less than 40 tweets and no day had more than 110 tweets. During session, however, the tweet rate varied more significantly; only 14 tweets were sent on Sunday, but 194 were sent on Thursday. Members were least likely to tweet during Saturday and Sunday, in both the session and recess observation period. Each tweet was coded according to two main characteristics: who issued the tweet and the type of tweet issued. All tweets were coded according to the issuer's party affiliation and whether the Member serves in the House or the Senate. All tweets were also coded into discrete categories concerning the type of message issued. To maintain consistency in coding, one author coded all of the data analyzed.