Sign Up
Signing up and using this site is free, because I'm a nice guy like that.
The reason you have to sign up to access some parts of Dofus Playground is because those parts want to keep information that you give it, for your use only. For example, the Market Helper helps you track your market listings in Dofus, so you can better tell what is and isn't selling, how much you've sold items for in the past, etc.
Your e-mail address is used as your login here, because that's the cool thing to do these days. I'd be asking you for it for password recovery purposes anyway. Also, I 100% promise not to share your e-mail address with anyone, because I wouldn't want to be an asshole, and sharing your e-mail address with anyone would make me an asshole.
P.S. You won't have to confirm your e-mail address, or anything; if you lie, it's your own fault when you forget your password.
P.P.S. Unlike some lame sites, Dofus Playground lets you use so-called "special characters" in the password. Go nuts. Use a percent-sign or something. It drives me crazy how many (more important) sites don't let you do this.