The Facebook founder ran the site by putting photos of two people of the same gender side by side. The user would then vote on the “hotter” person and then Facemash would present a final ranking. In just one day, 450 people had already visited the site and voted on people's faces over 22,000 times.
Immediately, criticism ensued. The Harvard student newspaper deemed his site improper, and Zuckerberg was accused of breaching security, violating copyrights, and violating individual privacy by Harvard's administrative board.
Zuckerberg took the website down, admitting that "issues about violating people’s privacy don’t seem to be surmountable. I’m not willing to risk insulting anyone."
On a less controversial note, high-school Zuckerberg built the Synapse Media Player, a machine that adapted to a music-lover’s listening habits, which was ranked 3 stars out of 5 in PC Magazine. It generated songs in a playlist according to someone’s taste, much like the discovery function of Spotify.