I got an invite over skype and thought "why not?". Turns out, this site was nothing short of a scam. I realized too late, unfortunately. I looked it up, and apparently, I'm not the only one who had this problem. So I say "DO NOT TRUST THIS WEBSITE AT ALL".
The domain registration uses a privacy protection service to hide the registrant's ID, and there is no publicly available information as to who runs the site or how to get in touch with them.
And best of all, when you sign up, you're asked to tick the usual box saying that you agree to the "Terms", but there doesn't actually seem to be any terms listed on the site.
I didn't bother completing the details on the first page to see what the rest of the registration process was like, but there seems to be various posts online from concerned people who have handed over credit card details.