Twitter, a microblogging site which allows users to deliver statements, thoughts and links in 140 characters to followers as well as a wider Internet audience, is the latest online communications technology adopted by MPs. Assessing the use by early adopters, this article considers which MPs are most likely to use Twitter (for example, tweeting), and how. Content analysis of MPs' Twitter feeds was conducted, and personal and political characteristics identified which may influence use. The data suggested that of the six characteristics tested, gender, party and seniority had most impact on adoption. Applying Jones and Pittman's 1982 typology, there is clear evidence that MPs use Twitter as a tool of impression management. Constituency service is a secondary function of the use of Twitter by MPs. Where MPs use Twitter as part of their constituency role it is to promote their local activity. This article notes that a small group of MPs use Twitter as a regular communication channel, but most are only occasionally dipping their toe into the microbloggersphere.