TECH
05/31/2011 07:51 pm ET Updated Jul 31, 2011

Facebook's First 20 Users: See How The Earliest Adopters Knew Mark Zuckerberg

If you look at your Facebook profile page (and you didn't opt to change the url to your name a few years back), the url is probably followed by a long string of numbers:

http://www.facebook.com /profile.php?id=5500957

That's likely the order* in which you signed up for Facebook.

When Facebook was first founded, every user was given an ID code. It began with ID #0, which redirects every user to their own profile page.

ID numbers 1-3 were likely tests that Mark Zuckerberg used and then deleted; the profiles no longer exist. The first real Facebook users start at ID #4.

Naturally, the first few people to sign up for Facebook were Harvard students. Some shared classes with Mark Zuckerberg. Others were roommates who helped him launch the site.

Zuckerberg's friends made up most of the ten first Facebook sign ups, after which the social network expanded to friends of friends across campus. Eventually it swept all ivy league colleges, the nation, and then the world.

Out of the first 50 profiles, only 6 are women. The first woman, Sarah Goodin, joined with ID# 33.

We found all of the first members, searched their friends, and found out how they were all first introduced to Facebook.

Read more on Business Insider's Silicon Alley Insider