While the numbers are nowhere near those of Facebook (really whose are anyway?) foursquare is experiencing some significant jumps in number of check-ins. This is a double-edged sword of sorts though since more and more people are discovering that when they have checked in they have essentially done everything they can do.

The Business Insider tells of the numbers that foursquare is reporting

Foursquare, the hot mobile “check-in” app, has basically doubled in usage over the last two months.
Responding to criticism for Foursquare’s recent downtime, the company said it’s now handling an average 600,000 “check-ins” per day.

That’s basically double the less than 400,000 check-ins per day in late March — just two months ago — and up about 5X from when it hit 1 million check-ins a WEEK in February.

With all of these folks figuring out that foursquare offers something different there is also the realization that check-ins are not unique to foursquare. In fact, other services like Booyah’s MyTown are getting investment dollars to move their needle as well.

So the question becomes as it is with any hot social media service: how will this make money? I am admittedly geo-location challenged. What that means is that I have not joined the craze so I have to be careful as to what I say about the viability of these kinds of things because frankly I am not a participant.

One thing I can do, as will many others, is look at the service and see just what marketers can do to leverage the interest of those who are involved. If the numbers reported by foursquare are any indication then the potential audience for marketers can become quite significant in a short period of time.

So where do you stand on the use of geo-location games / services? As a user and a marketer what are your impressions and how do you see these concepts making money? If there is any lesson to be learned from Facebook and Twitter, it may be that the sooner the decision is made as to how to monetize then there may be less headaches. Of course, when something starts free and then turns on its revenue efforts there will always be backlash no matter what the time frame has been from free to “not so much”.

So what’s your take? Foursquare, Gowalla, MyTown and others. How will they make money or can they make money at all?