Highlighting a social media as public records application, the Sunlight Foundation announced today that its research team has assembled a list of over 200 federal lobbyists currently using Twitter. The list was compiled by comparing a list of registered lobbyists against Twitter's list of user names using Twitter's API (Application Programming Interface). The Foundation then reviewed what its initial compare query returned and decided, based on the available biographical data in the Twitter profile, if the person with the Twitter account and the registered lobbyist were one in the same.
The complete Sunlight Foundation project description here. A story on the project via Politico here.
Along these same lines, this Bloomberg News article (as carried in the San Francisco Chronicle) is also worth a read for its discussion of how corporate researchers monitor LinkedIn, Twitter and Facebook for information about competitors and new business initiatives.