Trends in Twitter is a quick way to get a pulse on conversations. It is a snapshot of what the most Tweeted about topics are and to see what is important to a lot of people. If there is a drawback with it, that would be that it may be to encompassing. An event in NY may not be of much concern to those in California. Twitter has fully rolled out Local Trends allowing you to sub select trends in a specific area. It is easy to switch back and forth for you to get a pulse on the conversation in each area you care about. The number of locations is fairly limited at present, but Twitter is reported to be working to increase them. Give it a try.
"As Twitter evolves, and more people share what’s happening in their own world, we want to provide another way for people to discover topics that may be relevant to them. Last week we began to slowly roll out a new feature called Local Trends to expose what people are talking about on the state and city level, and today we've fully launched so everyone can use it."