Manhunt: did it. Adam4Adam: still doing it. Grindr: well, hello, my new friend! I no longer have to be at a computer--preferably my own--to find guys. I'm free! Want to find sex (and/or friends) on-the-go? Use Grindr. It's an 'app' for the iPhone that lets you connect with other users in your surrounding area. The setup is quite simple: you upload a picture and a small profile, and you're good to go. The app will give you the approximate distance to any given guy. You can chat, send pictures, and even give your exact location so the two of you can meet up. It's great. Since I've been using it, I've made small-talk with a handful of guys, hung out with two of them, and failed to follow through on a few sex offers. If I had a car, things might be easier.
One time I was told that a guy was zero feet away. I scanned my apartment; there was no sign of him. Another time, I was riding the bus home from work, and I noticed that the guy sitting in front and to the right of me was using it on his phone. I attempted to log on, find him, and send him the following message: "I'm sitting three feet away." Luckily, the program doesn't work that great, and he did not show up on my screen; if he had, I probably wouldn't have sent the message anyway. That's just fucking creepy.
The San Francisco Chronicle wrote a small piece on Grindr recently as well. Check it out here.