Posible memes to take into account: tags, urls, mentions, full tweets.
Detect the injection points of the meme.
Somehow map the propagation across diferent accounts taking into account the time. Crosscheck it with the retweet + mention network to see if the propagation is done mainly using the timeline (depending on the result it could be a paper opportunity). The be able to do this the twitter streaming should probably be tag directed instead of account directed.
Distributing this into more atomic issues (#9, #10, #11, #12). "Posible memes to take into account: tags, urls, mentions, full tweets" & "Detect the injection points of the meme." already done.