Mostly known for their frontman, Gaahl.
Gaahl joined Gorgoroth in 1998, and was first heard on their Nuclear Blast album Destroyer; however, he only sung on the title track.
Gaahl was sentenced to one year in prison for assault in 2001, and was forced to pay the victim 158,000 NOK (26,963 US$). In 2006, Gaahl spent another 9 months (of a 14 month sentence) in prison for brutally assaulting a man and allegedly threatening to drink his blood in 2002. The victim received a total of 190,000 NOK (32,424 US$). Gaahl was released in December 2006.
I suggest checking out 'Incipit Satan' if you want to hear more of them. You can also check out the documentary "True Norwegian Black Metal" on YouTube for a longer interview with Gaahl. (There's 5 parts)
Short interview explaining the ideology behind Gorgoroth(turn up your speakers):