Facebook now has 500 million registered users. That's half a billion people who have virtually "poked" their friends, shared more than 48 billion digital pictures and written trillions of messages on each others' "walls."

Six years ago this digital neighborhood didn't exist. Today Facebook, as a country, would have the world's third-largest population. That what happens when high-tech intersects with a basic human instinct to stay in touch.

Remarkably, in an age of Internet fads, Facebook has stayed alive by constantly introducing better and easier tools. And with customized systems that track our usage patterns and cater to our "likes," it's hard for many to disengage from the site.

Like the once "it" sites Friendster and MySpace, Facebook, in just a few years, could be a cultural artifact as well. It's still a business and it must profit off the intimate information that its members post. Members, increasingly concerned about privacy violations and aggressive advertising policies, just gave it a subpar rating in a customer-satisfaction survey.

There will be a next new thing. For now though, Facebook is still of the moment and this moment is worth recognizing. Culturally and politically influential, Facebook has "poked" it's way into the daily ritual of our lives. hN