Urban Dominik Müller is the creator of the brainfuck programming language, and consequently quite a famous person in the Esolang community. He is apparently not involved with esoteric programming any more, though.
In 1992 he created the Aminet Archive, a huge archive of freeware, shareware and open source software (including the original brainfuck distribution), images, music and other multimedia for the Amiga, which was at one time the largest software archive on the internet. He is the author of XPK compression package for the Amiga, and the Amiga version of CSH (the Unix C Shell).
He now works for search.ch, a Swiss search engine.