Street was hired by Blizzard Entertainment in February 2008, and was the lead systems designer on the MMORPG World of Warcraft until November 2013.[4] He described his role at Blizzard as, "Systems design specifically is everything that is not level, story, quest, PvP or encounter design. My team handles everything from mechanics to items to trade skills to achievements to UI design." On the World of Warcraft message boards, he is known by his user name "Ghostcrawler". Street worked in a similar capacity with Blizzard as he did with Ensemble as a designer. "Game designers are not artists or programmers, but we use the tools developed by the programmers and the assets created by the artists to get content into the game. Programmers make the game run, artists make it beautiful, but it is the designer's job to make it fun."