Facebook, the social network that once upon a time required a school email address to join, is becoming the communications app of the moment. And not just for young folks, either.

A lot of businesspeople, big-time bloggers and others are headed to Facebook. Why? Its open API -- and the applications being developed for Facebook -- are transforming it into a truly useful social network. Blogger Jeff Pulver says he's migrating from LinkedIn to Facebook:

Open APIs (application program interfaces) seem too technical to be truly important. Yet, for communicators they can create a whole new world of opportunity.

The recent trend of social media organizations such as Facebook opening their APIs to outside programmers means popular web apps -- including video -- can now reach members of these communities. Miller TV is a great example.