It wasn’t so long ago that people said Twitter was a huge waste of time. After all, who cares that I just ate a blueberry bran muffin? Better yet, why would I want to share that fact with the world? It turned out that users found valuable ways to apply the new tool. Pretty soon Twitter fostered new business relationships, altered the course of political protests globally and allowed those with special interests to find interesting and valuable information they might not encounter otherwise.

Now a tool called Foursquare is coming into the mainstream. You would be wise to take a few minutes to learn a little more about it. An article today on Mashable: “Foursquare Exceeds 40 Million Check-Ins,” would be a good place to start.

Basically, Foursquare uses the geo-location feature built into most phones to connect where you are with points of local interest. (Yes, there are privacy and safety issues.) Users can then check in to earn points and even see a map of where they are versus the check-in point. Check in often enough at one place, and you can become the “Mayor.” Businesses, in turn, can offer incentives to Foursquare users in close proximity.

For example, the Jimmy John’s near where I am staying in Austin, Texas, might offer a discount if I check in often enough. Or, they might offer a special known only to those on Foursquare.

It’s hard to say exactly what will happen with Foursquare. I have been playing with it, but don’t fully understand it yet. As my colleague Mark Vitullo from DigitalDay said as he toyed with it early this year

“If you want to use this for your clients, you have to start by figuring it out for yourself.”

Good advice for agencies, businesses, nonprofits—not always easy to follow with something new popping up every day, but darn good advice.