April 1st isn't the safest time to browse tech blogs on the web. One third of all of the posts that go up are likely a fake (this one, though, is entirely legitimate). Yet while Facebook's latest app looks like it could be a joke—it isn't. Riff is a collaborative way for friends to make videos with one another using the social network.

Riff1 Riff2 Riff3

Riff lets you shoot a clip that's up to 20 seconds long and share it for others to see.

Read More