I was lookng to find out why I had Not received any invites to give out ..so I looked around the Gmail site and this is what I found ""Gmail invitations are available on a
limited basis and are randomly distributed.
If you do not see the 'Invite a friend to join Gmail!' link in your inbox it means:
You have used all of your invitations or you have not been granted invitations
We are not distributing more invitations
We will not be able to give you more invitations, even if you ask nicely or offer to tattoo Gmail on some part of your body (You'd be amazed at what people will offer for a Gmail invitation.)
There is a sign up list for those who have not been invited, but want Gmail updates.""....
http://www.google.com/gmail/help/about.html#interest
Sorry
purplemtn