At the very least, exercise extreme caution combined with healthy skepticism. Don't fall for the trap of thinking that just because that Facebook message came from your mother, or that email was sent by your best friend, that it must be safe. Attacks like this spread by compromising one PC or user account, and then spreading to all of the contacts.

As for hyperbolic declarations of the end of the world--get used to it. Between now and the end of 2012, every event no matter how trivial will be a sign of the apocalypse to somebody. Should be a fun 18 months.