Twitter is as much a place for tech talk as it is for political discourse along party lines. Don't believe me, then check out this above graph of politically charged tweets.
The researchers behind this study used an algorithm to identify 250,000 tweets from 45,000 users discussing the 2010 midterm elections. They identified party affiliation and graphed both retweets and mentions from these Twitter users.
The plot of retweets on the left clearly shows that most people retweet along party lines, passing along information that meets their political leanings. Mentions, on the other hand, are evenly distributed with Twitter users communicating with colleagues as well as engaging opponents in highly-charged debates.