There have been few apps out for various devices over the years (current ones are mainly on the iPhone). There were even bluetooth ones, as someone suggested earlier, (mobiluck was one). Grindr, (which will soon be for more than just "the gays") is a popular one, but there are several others.

The problem is making app(s) cross platform enough to work on several devices. Even Grindr suffers in that it's "only" available for iPhone and Android devices, limiting it's potential. There are plenty of web-based sites out there that one could use on the N900 without a specific app. And more and more are making mobile versions with touch-oriented interfaces and lower bandwidth. (Current forms seems to be replacing www. with m. for the mobile site.)

Realistically though, if you're not gay and/or under 25, you're not going to find much out there. Women don't work the same way men do for the most part, and aren't looking for apps to find anonymous sex. Even if it were available, few women would download it, so it would turn into a sausage-fest rather quickly. (Try picking up women at a sports bar and you'll see what I mean.)

There's reasons straight matching sights tend to focus on dating and finding your "emotional" match and/or soul-mate. That's what women are looking for, and they're the ones that are the hard sell in this arrangement.

Now, if someone were looking to make a Grindr interface app for the N900, that may in fact boost sales. Lots of nerdy gay guys out there that would love to switch to the N900, but don't do so because they can't imagine going back to the pre-Grindr days. Besides, this forum could use a make over. I mean, seriously, gray and orange? This is place is so 1990.