While on Facebook this holiday season, watch out for The "Secret Sister" scam. It looks like it's coming back.

The scam first appeared back in 2015. It's all based on a chain letter system, but with money:

1) Send one gift value at least $10 to secret sister #1 below.

2) Remove secret sister's name from #1; then move secret sister #2 to that spot.

3) Add your name to #2 with your info.

4) Then send this info to 6 other ladies with the updated name info

5) Copy the secret sister request to your wall. If you cannot complete this within 1 week please notify me, as it isn't fair to the ladies who have participated and are waiting for their own gifts to arrive. Soon you should receive 36 gifts! Seldom does anyone drop out because it's so much fun to send a gift to someone you may or may not know."

Not only is this a scam, it's against the law and the US Postal Service has posted a warning on the hoax. So be careful not to get sucked into a scam.