Online sleuths are claiming to have discovered what could be Zuckerberg's first website - and it hints at what was to come.
The sparse looking site dates from 1999 and features a mention for Eminem, a blinking dinosaur eye, and at its centre a crude attempt to connect friends and "friends of friends."
Created when Zuckerberg was just 15 and living with his parents in New York state it appears to be the Facebook founder’s first effort at creating a social network.
Billing itself as "the only site where a yellow eye blinks with you" it contains myriad elements that may well now embarrass the Facebook founder.
It also hints at the young Zuckerberg's vision of the possibilities of the web.
The site, which was created by a New York teenager with the handle mez51, has just a handful of features, which include a "Zuck fader" and a "Cow-a-bungee" game.
"In a section called the "The Web", mez51 has this to say: "As of now, the web is pretty small. Hopefully, it will grow into a larger web. This is one of the few applets that require your participation to work well."
"If your name is already on The Web because someone else has chosen to be linked to you, then you may choose two additional people to be linked with."
"Otherwise, if you see someone who you know and would like to be linked with but your name is not already on The Web, then you can contact me and I will link that person to you and put you on The Web."
"If you do not know anyone on The Web, contact me anyway and I will put you on it. In order for this applet to work, you must E-Mail me your name and the names of the two people that you would like to be linked with. Thank you!"
The site, if it does indeed turn out to be the billionaire's fledging effort, also reveals the teen Zuckerberg was a fan of Eminem, AKA Slim Shady.
"Hi, my name is...Slim Shady. No, really, my name is Slim Shady,” the creator writes in the 'About Me' section.
"Just kidding, my name is Mark (for those of you that don’t know me) and I live in a small town near the massive city of New York. I am currently 15 years old and I just finished freshman year in high school."
The website was uncovered by a user on the Hacker News social network.
Although unconfirmed the site would appear to be a genuine early Zuckerberg effort.
Its creator is listed as Mark Zuckerberg and it includes an email that was used by Zuckerberg’s father Edward.
The site can be viewed here.