If you've heard friends & colleagues use the words FourSquare, Twitter, LinkedIn, Facebook, and Yelp but aren't sure what they're talking about, you might like David Pogue's New York Times article For Those Facebook Left Behind.
As a public service ... I’m offering a handy clip-’n’-save guide to the social networking services you’re most likely to hear about at this summer’s barbecues. (Warning: This is an extremely basic overview. If you’re already someone who, you know, tweets, this will all seem like old news. But it’s not intended for you.)
You can also view his 3-minute video that demonstrates all these social networking services.