Reading Intro News Today

Z finally this half hour, a social networking milestone. after just six years in existence, facebook, your favorite website, has 500 million users. >> i was just updating my status with reading intro right now live on tv. that means since founder mark zuckerberg started the site, 500 million people have poked, flagged, tagged and friended each other. bill weir has more. >> reporter: it is an engine of human connection. give facebook a few vital facts about yourself and it gives you a direct li...