The idea behind Photoswap is pretty interesting. The whole app revolves around just sharing pictures between users. What you do is you take a picture and it sends it off to whoever. Then it shows you a picture that another user has taken. You can then reply to that specific picture with another picture, or just send out a random picture again and see what you get in response.
The app doesn't allow you to use exisiting pictures or save those pictures that you've taken with this app for use in other places. That means that you may have to sacrafice a really nice picture to send to some random stranger instead of just saving that picture in on your phone. The camera snaps the picture just as well as the regular app does. Plus the quality stays in tact as you can tell from the received photos.
Photoswap isn't for everyone. You have to really enjoy seeing new and weird pictures, plus there really isn't a content filter, so you never know what you're going to get (in 30 minutes of use, there were no inappropriate pictures). You can set your own username or just use whatever default one they give you, but these options aren't in the app, they're in the iPhone settings area.
You can actually see the location of who sent you the picture. Considering theres a function that pulls it up in Google Maps, it would be amazing for it to let you put a little tack in the map showing that you've received images from there. People all over the world are using this app, so it's pretty neat what you can see. But overall, this isn't something that will catch on for anyone who isn't a photography fanatic.