Im doing a Java application where I'll have to determine what are the Trending Topics from a specific collection of tweets, obtained trough the Twitter Search. While searching in the web, I found out that the algorithm defines that a topic is trending, when it has a big number of mentions in a specific time, that is, in the exact moment. So there must be a decay calculation so that the topics change often. However, I have another doubt:
How does twitter determines what specific terms in a tweet should be the TT? For example, I've observed that most TT's are hashtag or proper nouns. Does this make any sense? Or do they analyse all words and determine the frequency?
I hope someone can help me! Thanks!