How do the trending topics work on twitter, and when do you use them?

[Morgan]

[@GoshhCelina]

Trending topics are things that people are talking abt most in their tweets.
For example: when you see something likle #nowplaying people are talking about what they are listening to or etc.
for others, like the Haiti problem they just talk about it.

the more its talked about, its on the top.

you can use it when ever you put that word in your tweet.