Why use invite codes?

[Bluem00]

You've built a cool website and want to get some real, actual, users. In this situation, some companies create a mechanism by which only people that have invite codes can log in, and then these people are given a few invite codes for their friends. What is the reason to use invite codes in this manner as opposed to just allowing anyone to sign up?

Is it a marketing ploy, attempts to limit server load, something to make TechCrunch write about you?

Thanks!

[blogimus]

Invite codes are a good way to limit access as you ramp up and also let you have a rough idea of which users are externally connected, even if it is not very accurate.

I'd say use as a marketing ploy is limited, unless one can successfully foster some kind of "gotta have" site before and during launch, and the vast majority of sites don't fit this bill.

[fromedome]

All three! Same reason nightclubs keep a line out front even when they're half-empty.

[jdavid]

its part of your story. people like to have something of value. inviting someone else allows them that chance.