Samy Kamkar too for writing the Samy MySpace worm.
From Wiki:
>Samy Kamkar, the author of the worm, was raided by the United States Secret Service and Electronic Crimes Task Force in 2006 for releasing the worm.[4] He entered a plea agreement on January 31, 2007 to a felony charge.[5] The action resulted in Kamkar being sentenced to three years probation with only one computer and no use of internet,[6] 90 days community service, and $15,000-$20,000 USD in restitution, as directly reported by Samy Kamkar himself on "Greatest Moments in Hacking History" by Vice Media's video website, Motherboard.
It can be a punishment for certain crimes- or as an extended punishment after jail. Things like stalking where a computer was a primary method, valid threats made on a computer, etc.
Who is banned from using computers? You mean, in prison?