This plugin allows users to send invitations to friends and colleagues. Users can include a personal message along with the invitation.

As you can imagine, this is pretty powerful stuff, the real fans of your site can collectively contact tens of thousands of people telling them how great it is!

If you're an advanced developer type too, you can even integrate this with a system that will allow your users to import their email contacts from web based email services like hotmail, yahoo or gmail - and then email the lot of them!

Below is it in action at Edublogs: