Social network analogies
I heard an excellent set of social network analogies from Steve @spatrizi Patrizi, LinkedIn VP of Advertising Sales And Operations. He cited LinkedIn founder Reid @quixotic Hoffman: MySpace is like a bar where you go for entertainment and music, Facebook is like a backyard barbecue [a "cookout," if you're in the south of the U.S.] where you hang out with people you know and maybe let them walk through parts of your house, and LinkedIn is like the office. That makes a lot of sense to me.
I'd add that Twitter is a 24x7 party where your followers are like the people at the party you're listening to, and your followers are listening to you. If you follow each other, you can have conversations. But those are conversations in the party with other followers. You can whisper to someone using direct messages. You can seek out interesting conversation by searching on hashtags and keywords.
So users of Foursquare: what's that like? I don't get their description. Explore my city? I'm a rural kind of guy. Why are some saying that Foursquare is "next year's Twitter?"