What was the first app to do a staged rollout or invite-only launch?

It's commonplace these days for apps to do "staged rollouts" or stagger invites for new adopters.

This trend obviously grew from the concept of pre-launch email signups, and seems to have turned into more of a marketing gimmick than actual necessity. Smaller apps and startups have adopted the practice from big boys like Google to enhance their image.

To me, this is the digital equivalent of making you stand in line to get into a club - making it appear more crackin than it actually is.

My question is - what was the first app or service to do the whole "invite" thing?