In case you’re looking for historical data within Twitter, this might help you:

Have you ever sent out a “tweet” on the popular Twitter social media service? Congratulations: Your 140 characters or less will now be housed in the Library of Congress. That’s right. Every public tweet, ever, since Twitter’s inception in March 2006, will be archived digitally at the Library of Congress. That’s a LOT of tweets, by the way: Twitter processes more than 50 million tweets every day, with the total numbering in the billions.

The Library states…

The Library did not pay for the archive; rather, it was a gift from Twitter.…
Tools and processes for researcher access will be developed from interaction with researchers as well as from the Library’s ongoing experience with serving collections and protecting privacy and rights.
Individually tweets might seem insignificant, but viewed in the aggregate, they can be a resource for future generations to understand life in the 21st century.
Twitter is part of the historical record of communication, news reporting, and social trends – all of which complement the Library’s existing cultural heritage collections. It is a direct record of important events such as the 2008 U.S. presidential election or the “Green Revolution” in Iran. It also serves as a news feed with minute-by-minute headlines from major news sources such as Reuters, The Wall Street Journal and The New York Times. At the same time, it is a platform for citizen journalism with many significant events being first reported by eyewitnesses.
The Library of Congress collections include items such as the very first telegram ever sent, by telegraph inventor Samuel F.B. Morse, oral histories from veterans and ordinary citizens, and many other firsthand accounts of history. These collections and others have left behind glimpses of the lives of ordinary people, thereby enriching knowledge of the context of public events recorded in government documents and newspapers.

How can this help AV Research?

Since the feed will be public and historic, there is a potential to research trends over the timeline, particularly as twitter is being used for more command and control functionality. As soon as it becomes available, we’ll follow up. :)

As one of the commenters on Library of Congress’ site commented:

Making all tweets available to all researchers will enable more researchers to study the evolution of the use of this increasingly popular social media tool.

Another commenter noted the impact to privacy: