My brother has had it on his phone for months and I initially rolled my eyes as I saw him “checking in” at a restaurant.

“Why on earth would you want people to know where you are at all times?” I asked. I don’t remember the response, so I’d guess I wasn’t impressed.

As time went on, I noticed that a few Facebook friends were using the app, as well. I still had no idea why. Nor did I care enough to inquire.

But guess who was listening to Wall Street Journal This Morning? Low and behold, Gordon and the gang had a segment on Foursquare. Maybe this means I don’t take anything seriously unless it’s on WSJ. Hard to say…

Anyway, here’s what you need:

• cell phone
• foursquare
• “a passion for exploration”

I’m guessing a smart phone is probably the easiest way to utilize this app, but apparently if you can text, you can check in wherever you go that way, too.

Here’s why you may want it, according to the foursquare team:

Foursquare is a mobile application that makes cities easier to use and more interesting to explore. It is a friend-finder, a social city guide and a game that challenges users to experience new things, and rewards them for doing so. Foursquare lets users “check in” to a place when they’re there, tell friends where they are and track the history of where they’ve been and who they’ve been there with…

As of last month, there were already 4 million users and “10s of thousands of participating businesses.” And why not? Browsing some of the local businesses in my neck of the woods, I found deals like $10 off a $50 purchase, half-price deals and even a free T-shirt for the “mayor” of a certain business. So maybe it’s worth checking into!

Well, my brother just called, conveniently interrupting me while asking what I’m writing about.

“You’re only about a year behind,” he said. “You need to be writing about Groupon.”

I told you. I’m always the last to know…

-Liz