BlizzCon is Blizzard Entertainment. They made monumental gaming classics such as Starcraft, Warcraft, World of Warcraft and Diablo. Its their gaming convention. I'm a massive fan of blizzard games, as they are some of the most intellectually stimulating and addicting games I've ever played, and I've only heard wonderful things about BlizzCon.
With that being said, many people at BlizzCon will be happy about Blink 182 performing.