Truthy [indiana.edu] is a recently developed online system to analyze and visualize the diffusion of information on Twitter. It evaluates 1,000s of tweets an hour to identify new bursts of activity around specific topics and memes, to reveal when, where and how they emerged .

For instance, Thruthy claims it can distinguish organically emerging grass-roots viral campaigns from those that forged (i.e. 'astroturfing', which denotes political, advertising, or public relations campaigns that are formally planned by an organization, but are disguised as spontaneous, popular 'grassroots' behavior). It therefore uses a combination of text and data mining, social network analysis, and complex networks models, together with a training algorithm based on input from users who are invited to flag dubious injections.

Next to a network diagram that shows the relationships between Twitter members that retweet or mention a specific of meme, the interface also contains a meme activity timeline graph and various numerical statistics and mood-identifying semantic analysis results.

For more information, see also here. See also Tracking the Mood on Twitter.