#8 - March 31, 2010, 7:17 p.m.
The in-game whisper you received was not sent by a Blizzard representative. Instead, it was sent by a malicious party (likely from a character on an already-compromised account) in attempt to "phish you," or lure you to a site capable of gleaning account-specific information. You can learn more about these types of phishing attempts here:
http://us.blizzard.com/support/article/30829 You were to remain cautious, Bübbles. Should you ever receive such a message in the future, though, go ahead and right-click the author's name and select the "Report Spam" option. This will automatically file a report and place all characters on the author's account on ignore for the duration of your login session. :)