[mark_l_watson]

There is always the garden hose sample feed from Twitter. Or, use this service for short test intervals.

Seems like data hackers are being taken care of.

Also, if you want a lot of social media cheaply, check out the sample web app for Google Buzz that runs on AppEngine. I ran it last summer with some of my own filters. I could run it about 5 hours a day before I hit the limit of a free AppEngine account - so it would not cost too much to pay to keep a derivative of this example program running 24x7.