I signed up because i was interested in a game, called Artifice and I signed up with my Email and Username, and got the Promotion Code "4TA33MPFKX4M" - When I entered it into iTunes it said "This Code has already been used, etc" So I am both very and . - I entered my email into a website i barely even knowing this site, and I automatically get nothing. Now I'm afraid of receiving spam.
It's not the site's fault, the developer must have accidentally submitted a code that they'd already given to someone. I'll do the same game and PM you the code, see if it works.
I've gotten quite a few codes off of the site, and only one has failed me (expired.) As for spam - the account I used already gets a ton of spam, so I have no idea if they're selling your address or not. They do seem to be on the up and up though.