Twitter corpus for Sentiment Analysis from a class (cs224n)at Stanford.
Class page:
https://sites.google.com/site/twittersentimenthelp/for-researchers#Where_is_the_Tweet_corpus_8553
http://www.stanford.edu/~alecmgo/cs224n
S. Vieweg, A. Hughes, K. Starbird, and L. Palen. Proceedings of the SIGCHI Conference on Human Factors in Computing Systems, page 1079--1088. ACM, (2010)