Facebook users are mistakenly sharing a warning with each other about how to behave in voting booths during today's elections for the American presidency.
The kindness of friends is helping perpetuate an ongoing hoax that has spread widely across Facebook.
If you've seen such a message, posted by one of your Facebook friends, do them and the other billion users of Facebook a favour, and tell them that it's a hoax.
You shouldn't forward chain letters even if they're true. You definitely shouldn't forward them if they're false.
And the latest false warning doing the rounds is a perennial hoax - the so-called Invitation FACEBOOK/Olympic Torch virus warning.
Twitter was all a flutter this weekend with users reacting to the alleged death of music star Gotye.
And although the news appeared on a CNN website - it doesn't mean you should believe it.
Has Vanilla Ice really died in a car crash?
After all, plenty of people have been sharing the news on Facebook in the last 24 hours - so it must be true, mustn't it?
Facebook users have been spreading a chain letter recommending that their friends post a notice to their walls prohibiting Facebook and the US government from using their content. It is a chain letter/hoax and has no legal merits.
Facebook users are sharing messages warning that children are being targeted with strawberry-flavoured crystal meth.
But is there any truth in the widespread warning?
Facebook is to end on March 15 2012, claims the Weekly World News... and many Facebook users seem to believe it.
Facebook users are innocently sharing advice with their online friends about how women can avoid being kidnapped and raped, not realising that they are perpetuating a hoax.
Tens of thousands of Twitter users have been tricked into retweeting a message claiming that Twitter will donate $1 per retweet to a baby needing treatment for cancer.
Of course, it's a hoax.
Has 1980s pop star Adam Ant really been killed in a jet ski crash?
If you believe everything you read on Twitter and Facebook, you might think that it's true. Learn to be more skeptical, and don't trust everything you read on the net.
A message spreads on Facebook telling you how you can send a Christmas card to an anonymous American soldier - but all is not what it seems.
Almost 200,000 Facebook users have been duped into sharing and reposting a message about a 14 year old boy who was allegedly beaten badly by his stepfather after protecting his little sister from being raped.
A new hoax is spreading between Facebook users, in the mistaken belief that sharing a picture of a sick boy in intensive care will grant him a heart transplant.
A warning is being spread by Facebook users, worried that their friends may have caught a computer virus because their profile picture has gained a pink tinge.
Find out how a campaign to raise awareness and money to fight breast cancer turned into a computer virus scare.
Millions of BlackBerry owners around the world have been feeling the pain this week as messaging and email systems collapsed in a service outage.
Which is hardly the ideal time for a BlackBerry-related hoax to be spread.
Duped Facebook users are sharing a message with their online friends, believing it will help them avoid charges of between $3.99 and $9.99 per month.
Of course, the chain letter is completely bogus - and should not be forwarded.
Will Facebook start charging due to the new profile changes?
But don't let the truth get in the way of a good old-fashioned chain letter, spreading like billy-o across the social network.
A warning is spreading like wildfire on Facebook, claiming that hackers are posting pornographic movies on users' walls which are invisible to the owners of the wall but are visible to friends and family.