Activision-Blizzard filed its annual 10-K report on March 1st, and Robert Purchese of Eurogamer has dug up some interesting information found in the report regarding World of Warcraft's future.

One section of the report mentions that the emerging casual games market on the iPhone and social media sites such as Facebook could directly impact World of Warcraft sales, if not render the game "obsolete":

We also compete with other forms of interactive entertainment, such as casual games like iPhone applications and other mobile phone games, and games developed for use by consumers on social networking sites. Future increased consumer acceptance and increases in the availability such games or other online games, or technological advances in online game software or the Internet, could result in a decline in platform-based software and negatively impact sales of our console and hand-held products. Newer technological advances in online game software may also render products such as World of Warcraft obsolete. Additionally, direct sales of software over the Internet by competitors could adversely affect our distribution business.