When building a new Web 2.0 site, especially a new social network, there’s always one hurdle that needs to be overcome – establishing a large enough userbase to make it both attractive to newcomers and worth using once you arrive.

ReadWriteWeb reports that a new site, Spiffbox, thinks they have figured out how to workaround this issue – they’re paying users to participate. Every action you take on the site including responding to emails, chats, friend invites and sharing photos, will earn you points which can then be redeemed for cold, hard cash.

Spiffbox is also different in the fact that it’s not entirely meant to be just for socializing – it wants to help you promote your career as well as ask for and receive advice from other users.

Of course what everyone wants to know is: how do you make money on Spiffbox? Basically, all that you need to do to start earning is participate.

To earn points, users should create a profile, communicate with other members, respond to messages, and optionally complete surveys or take merchant offers. With each action, more points are earned and when you reach a certain threshold (min. 2,000 points/$20), Spiffbox puts a check in the mail.

You may be surprised to learn that reaching that payout number is not as hard as it may sound. Accepting a chat invite earns you 28 points, accepting a friend request is 10 points, and so on.

After spending some time really engaging on the site, you could easily start earning cash.

Photo by Spiffbox.