They're now handing out invites at the main search page. There was a link to oin right under the search box, where they put the new feature announcements.

Grady, could you make a screenshot for us?

Thanks, I've got a screenshot now.

A 1st April international release wouldn't seem stupid to me...
Do they still have the right to joke?(with all the money involved now)
What are they going to find as a fake april fish?
What will be the real one?