If you're online—and reading this!—you've probably heard of Twitter. But just what is Twitter for? How does it work? And how do you get started using it? Whether you want to start using Twitter ...

Rafe Needleman reviews mobile apps and products for fun, and picks startups apart when he gets bored. He has evaluated thousands of new companies, most of which have since gone out of business.

Twitter is preparing to launch several impressive new features, including a new streaming API that will give desktop client applications real-time access to the user's message timeline. The new ...