BBC News is carrying an article about the Microsoft Windows Animated cursor bug, and how crackers are using it to target World of Warcraft players. In brief synopsis, visiting compromised websites could infect your machine (via the ANI bug) with essentially a keylogger that sits dormant until you fire up WOW and log in. At that time it sends the data to someone else. Microsoft broke their normal patch release cycle to release a patch that will hopefully fix the flaw.
source: news.bbc.co.uk