It's kind of lame unless using Facebook is what you spend the bulk of your time doing on your smartphone.
But we were pretty impressed with a new feature called Chat Heads, which makes it easy to send text messages and Facebook messages while you have any app open.
For example, if you receive a new text while checking your email, you don't have to close the app to respond. The message just floats on top of whatever app you have open at the time.
Here's a video demo:
Pretty cool and useful, right?
Texting is so common and pervasive on smartphones that it'd be great if others took a cue from Facebook and copied Chat Heads.