Harris and Klebold linked their personal computers on a network and played video games over the Internet. Harris created a set of levels for the game "Doom", which later became known as the 'Harris levels'. The levels are downloadable over the internet through "Doom" WADs. Harris had a web presence under the handle "REB" (short for Rebel, a nod to the nickname of Columbine High's sports teams) and other online aliases, including "Rebldomakr", "Rebdoomer", and "Rebdomine". Klebold went by the names "VoDKa" and "VoDkA", seemingly inspired by the alcoholic drink. Harris had various websites that hosted "Doom" and "Quake" files, as well as team information for those with whom he gamed online. The sites openly espoused hatred for people in their neighborhood and the world in general. When the pair began experimenting with pipe bombs, they posted results of the explosions on the websites. The website was shut down by America Online after the shootings and was preserved for the FBI.