Firstly, I know that you can sign up without an invite but it is limited to 50 new users a day so it is hit and miss.
I have 12 invites to give/swap.
3 conditions though.
1. Proof of ratio from at least 2 sites.
2. Promise to give back what you take.
3. I can only send invites to @yahoo.com or gmail.com
Cheers
