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
Citizen Journalists: We are now Frictionless neighbors, World-news curators, Cultural translators, Censorship invaders and Content creators. Great video with examples.