PhotoFunia
PhotoFunia is not a very good site compared to the program Photoshop. You don't need any creativity to use this site. All you have to do is pick a cool effect from the lists of them and pick your photo. It's very easy to use. I think their target audience is your kids probably between the age of 10 and 13 who want to use this website to make "cool" photos to put on FaceBook.
Photo 505
Photo 505 is almost the exact same thing as Photofunia. They both give you certain effects that makes your photo look cool. There is no creativity needed. I think their target audience is the same as Photofunia, probably Tweens.
PicMonkey
PicMonkey is a lot better than most of the other photo-editing websites. There is still not a lot of creativity needed to use it unlike Photoshop. The website lets you use certain tools like the tools in Photoshop like the burn tool, etc. It also gives you a choice to use a preset setting that lets you do some really cool things to the picture like "zombie-fying"it. I think the target audience is mainly teens. This is a pretty cool website.
Citrify
Citrify is another program that gives you a lot of freedom to do what you please. You can change the brightness, take off blemishes, and lots of other stuff. It also gives you effects like the "Obama Effect." And you can also add stickers of lips, hair, and other stuff. This is a lot easier to use than Photoshop but it doesn't give you nearly as much freedom. I think their main target audience is Teens.