With increasing need for adult care, nannies or other kinds of caregiver services, scammers see this as an additional source of revenue. They may victimize job seekers who have sought employment from such sites as Care.com. These sites can be a convenient and efficient way to drum up business and provide a useful service. But scammers can misuse these sites.

 Details vary, but in general the scams works like this:

Someone replies to your listing on the site, saying they want to hire you to care for their child, parent or even a pet. They may have a very persuasive story that tugs at your heartstrings, such as a purported need for special items or medical equipment their loved one will require while in your care. 

They send you a check in a substantial amount to be deposited in your bank. They ask that you keep some of the money as payment for your services, and then transfer the rest to a third party, supposedly to pay for the goods that you will need while serving as a caregiver.  The scam is revealed only after the bank discovers the check is a fake.

The scammers take advantage of an unfortunate weakness in the banking business. Your bank is required to promptly make money available to you after a deposit in your account. But it may take several days for the bank to determine the check is phony. If you have already withdrawn any of the money, you are on the hook to repay the bank. If you have already transferred money to the third party, it's gone.

This is a variation of the old "You have won the Lottery" scam in which the victim  receives and deposits a phony check in some large amount but ends up owing a bank for money withdrawn or forwarded to the scammer for a purported use such as "Payment of US Taxes".