WIRED reported on the recent rumors that've started on the European WoW forums, and circulating everywhere else by now, that running Windows Media Player in the background while playing World of Warcraft shortens load times:

After noticing the folks at WoW Insider offering their own anecdotal evidence for the viability of these claims, I attempted to test the method myself. By opening Windows Media Player, leaving it idle, minimizing it, then playing WoW, I did in fact notice shorter loading times, specifically in high-traffic sections of the game.

Whether this is a Microsoft sponsored propaganda, or a weird accidental phenomenon, Blizzard stated that they've acknowledged "the issue" and are looking into it.

Let us know if this "tweak" works for you!