What is everyone talking about or searching for right now? Knowing the terms that are trending at this moment is like knowing the news. With a new API your apps can be just as aware. Lets Be Trends provides programmatic access to the most popular keywords on Twitter in realtime (details at our Let's Be Trends API profile).
It also offers explanations as to why each is popular, similar to the Twitter hashtag explainer, only this also includes non-hashtag terms. The explanations for trends come from users of Brizzly (the API comes from Thing Labs, makers of Brizzly).
The API itself is fairly straightforward: it's RESTful, returns data in JSON or Atom, and has just a few methods. The primary functions are current_trends, that gives you list of trends, and get_trend which gets you details on a specific trend. There's also an experimental feature that lets you get information from certain international locales.
Currently Lets Be Trends only uses Twitter, but it plans to add other services. Twitter, of course, seems the most useful at the moment. That could change as more services make their data available. For example, large sites might open a portion of their analytics in realtime, or share the most-searched items (similar to the way Google News highlights popular search terms).
Trends themselves are trendy. Recently we covered a powerful mashup that overlays trending terms on a map. Let's Be Trends could eventually fuel similar mashups, especially as geographic segmentation becomes more popular.