Foursquare founder Dennis Crowley (flickr.com/vadimlavrusik)

One day in the future, we will look back through the lenses of our Google Glasses and remember this week as the week that popular New York startups gave in to the inevitable: the inevitable being advertising, of course.

On Wednesday we reported that, despite founder David Karp's publicly noted distaste for ads, Tumblr would be opening up the Tumblr Radar spot to brands. Now, it looks like Foursquare is following suit. AdAge reports that the mobile check-in app will be launching a paid media platform in mid-June.

According to AdAge:

The new product will allow merchants to promote a deal to check in at a given area through its existing merchant platform, which allows businesses to claim their Foursquare listings. When users search for local specials, they can see offers via paid ads on Foursquare. Those ads will be targeted using the same algorithms that power "explore," which recommends establishments based on a users' past check-ins, as well as those of friends and the wider Foursquare user base.

With the announcement that Foursquare has reached 20 million users and two billion check-ins, it's unsurprising that the company would want to seek out further ways of monetizing those users. And a paid media platform is much more expected than the news that we reported yesterday, that the company had signed with a Hollywood talent agencies to incentivize celebrity check-ins.

Both moves signify a company attempting to strike out into the mainstream and capitalize on their continued growth. Plus, Foursquare has some pretty fierce mobile check-in competitors in Facebook and Google.

Foursquare hasn’t officially confirmed AdAge’s report, but fell back on boilerplate when asked for comment. "Our goal is to build scalable self-service tools that enable businesses to draw in new customers and retain and reward their most loyal ones, while also enhancing the Foursquare experience for our 20,000,000-strong community," a representative told AdAge. We're reached out to Foursquare for comment and will update if we hear back.

Looks like Mr. Crowley will have a lot to catch up on when he returns from his tropical family vaca.