Attention all Facebook users: You will not be able to access the social-networking site on Feb. 29, 30 and 31.
"Share this message with at least 15 of your friends for the best chance of alerting everyone," reads a message circulating on Facebook. "Many people will try to log in from February 29 to 31, just to find the site closed down for those days with no warning."
The message is absolutely right. You can't use Facebook on those days, because those particular days don't exist in February this year.
Funny, up to a point
The message, reported by Sophos' Naked Security blog, is one of several Facebook scams, jokes and hoaxes that have circulated in the past few years.
More serious are the scams that con you in order to make money, such as the one promising a free Facebook T-shirt (it asked you to take a survey), or the one that Mark Zuckerberg will personally give you an iPad (in exchange for your email address and other personal information).
Even worse are fake Facebook pages hosted on other sites, which are designed to capture your username and password for the 800-million-strong social network. Facebook's done a good job of keeping malware out, but once you go off-site, you're on your own.
Safety sometimes breeds complacency
By adding email, instant messaging, search and video features over the past few years, Facebook is aiming to be the Internet for its users.
The same thing happened in the 1990s with AOL, which replicated almost everything available on the wider Internet within its own walled Disneyland.
For many AOL users, AOL was the Internet, partly because AOL's dial-up subscribers had to go through the service to reach the real Internet. The business model collapsed when affordable broadband connections reached most residences in the United States after 2000.
But both then and now, there are millions of people who trust their particular service and don't care to see what's beyond its walls.
It's those people who are targeted by Facebook hoaxes and scams, in the assumption that they'll believe the scams and forward them to their friends.
Instead of becoming one of those people, ask yourself whether something's too good to be true, and then trust your instincts. That's true both on Facebook and on the Internet as a whole.