Want to spam your friends for fun (and no profit)? Sign up for this social networking site, make the wrong choice when asked, and you'll end up spamming them just like one of those old viruses that checks your address book and sends copies of itself to everyone.
If you accept an invitation, and you happen to ask it to check your friends in your address book (come on, it's so new, why bother!?), you'll spam them with invitations. Worse, the email looks as though you sent it yourself, so they may end up getting irritated at you for no good reason.
We've given you fair warning! This is rather Draconian, to say the least. Unfortunately, this publicity is not likely to turn into massive numbers of new signups for them.