The holiday season is almost in full swing -- and just like every year, expect to see those pesky "gift exchange" posts from your Facebook friends.

We wanted to Verify: Is this a harmless Facebook scam or can you get into real trouble with the law for spreading it?

The "secret sister" scam promises if you kick in a $10 gift, you'll be given between 6 and 36 gifts in exchange.

According to the US Postal Inspection Service, these chain letters are illegal: they're requesting money or other items of value, and promising a substantial return to the participants -- a return that's highly unlikely in the first place.

The "secret sister" scam is nothing new. Similar scams have made the rounds on Facebook in past few years, including book exchanges.

Mathematicians - and the postal service alike - say there's no way everyone can come out with 36 gifts or books.

Not only are these posts pyramid schemes, meaning those at the bottom of the chain likely get no gifts at all, but they're against federal law.

Participating in these schemes is considered a form of gambling, and sending gifts or money through the mail to satisfy requirements violates federal law. If convicted, you can be jailed for up to two years.

And though cops aren't scouring Facebook to arrest you, know your identity could be stolen if you're giving out your personal information, like your address or phone number, to strangers.

If you do spot the scam on your Facebook page, your best course of action is simply to ignore it.

The Oregon Attorney General's Office hasn't received complaints about this specific scam, but they say you should always read the fine print.

"As soon as you send over cash or a gift card, it is out of your hands and you have no way to get it back," Kristina Edmunson with the Attorney General's Office said in an email.