Data breaches cost a lot of money, consumer satisfaction, and trust. In the MMO world, the trust that exists between the game's developer and the player is a tricky relationship to navigate and extremely fickle. Any number of wrong moves or postures can turn your profitable subscription MMO into a public relations nightmare forced to turn the wagon around mid-trip. Security compromises a large part of that MMO trust.
Blizzard has had its fair share of security issues and trust problems between the players and itself. As the first MMO to have to battle hackers and not just gold farmers to the scale present in WoW, Blizzard had to invent its own way to do business in the world as it was -- an insecure place dominated by gray-market gold sellers and account hackers looking to sell to an eager, ready-to-spend playerbase. While WoW isn't the astronomically large service that some others affected by recent and notorious hacks are, it serves as an example of one of the big guys in the industry doing their best to navigate a minefield.
Greg Boyd and Gary Kibel wrote an article for Gamasutra discussing seven steps to improved security in the online and gaming space. After reading over the article, I felt that many of the points discussed had Blizzard and WoW-specific analogs and real-world examples that might shed some light on the security concerns still out there, what WoW has accomplished in the MMO security space.