Laurence Mason's character Lord Nikon was given the name because of his photographic memory.
When MGM/UA set up a website for Hackers, it was like dangling candy in front of a child. Soon after the site was established, it was hacked! A group calling itself the Internet Liberation Front managed to 'doodle' all over the photograph of Hackers stars Angelina Jolie and Jonny Lee Miller, and replaced verbiage, 'this is going to be an entertaining, fun promotional site for a movie,' with 'this is going to be a lame, cheesy promotional site for a movie!' The studio decided to maintain the site during the theatrical run of the movie in its altered form."
Ramon, a.k.a. Phantom Phreak takes his name from a combination of several items/people. Phreaking is the term for hacking phone lines. Also, Phantom Phreak refers to himself as "The King of NYNEX" when he introduces himself to Dade, a reference to the telephone company which served the New York City area at the time the movie was produced. His name is also a reference to "Nynex Phreak," a member of the Masters of Deception, a New York-based hacker group. This is also the joke when Joey suggests the Master of Disaster as his handle.
When Eugene "The Plague" Belford, is on the plane near the end of the film, he uses the pseudonym "Mr. Babbage". This is a tribute to Charles Babbage, the inventor of the first finite state logic machine, a predecessor to the computer.
Zero Cool, is based on Robert Tappan Morris, who was an associate professor at Massachusetts Institute of Technology. He is best known for creating the Morris Worm in 1988, considered the first computer worm on the Internet.
The handle Crash Override is taken from Flash Override, the highest priority level in the Autovon system.