The "Keep me posted" link on their home page returns a 404:

https://www.google.com/intl/en-GB/+/learnmore/notifyme.html

A bit strange to see a rookie mistake like that from Google, given the fanfare over this thing.

I have a bad feeling this is going to be like Wave - those people who do get invites have nobody to talk to so by the time everyone else gets invited the interest has peaked.

I really hope not, though. Facebook seriously need competition.