Foursquare just took a $20 million venture investment that valued the social network at $95 million. Congratulations, preening "mayors:" Your obsessive "checking in" with Foursquare's mobile software has been successfully monetized.

The company has taken in money before, but not on this scale; Foursquare's original funding round in September 2009 was just $1.35 million, followed by a presumably lower "bridge" round. But as use of the location service has mushroomed, so has the interest of Silicon Valley's deeper pockets, including Yahoo, believed to have bid close to $100 million for Foursquare in April, and Facebook, which reportedly held talks as well. Andreesen Horowitz, the venture firm putting in the current $20 million round, also approached Foursquare in the spring before giving up.

Kara Swisher at All Things D, who predicted the acquisition last week, says the interest in Foursquare is "overhyped... it is not clear yet if that [popularity] will translate into solid businesses." In fact, it's not even clear if Foursquare, useful mainly as a way for overwired young urbanites to posture or, just as perilously, stalk private gatherings, will ever be refined into something genuinely useful for a substantial portion of society. It certainly seems possible, with enough focus and iteration. But over the past six months the company seems to have had the attention span of a drink-slamming club hopper. Maybe Foursquare's new investors can help focus and formalize the startup a bit. But, given that partner Ben Horowitz announced the deal with the following rap quote, it's hard to be too optimistic about that:

They say he's a grinder
fly ass rhyma'
With a CEO's mind bra'
–Kinfolk Kia $hine

[Pic: Foursquare CEO Dennis Crowley poses during a portrait session at the Digital Life Design (DLD) conference in January. Getty Images.]