I heard this on NPR this morning. The Massachusetts Historical Society have set up a Twitter account for the late president John Quincy Adam. They will be tweeting from Adams' diary following his journey to Russia to become our ambassador there in 1809. I love history, so it will be interesting to get these succinct entries from his diary.
http://www.nytimes.com/2009/08/06/us/06adams.html?hp
You can follow at: JQAdams_MHS