Who is responsible for credit card debt?

You are not responsible for someone else's debt. Period. An authorized user is not a card-holder.
Creditors will call and call, send threatening letters and may even come knocking. Once the card holder dies, the estate takes over. Again, you are not responsible, even if you are the executor or the Personal Representative. If there is no money in the estate, i.e... house sold, proceeds passed on to heirs, then the creditor is out of luck. Most creditors either ignore the situation or they go after the estate. They wait in line until their turn appears on the court docket/. It may take years.
Executor or P.R. must remember to do two things after the death of the debtor: First, file an exemption with the fed and state indicting that the estate is worth less than the taxable amount on the Estate Tax: 2012: $5,000,000. 2013: $1,000,000.
The only action a creditor may take is filing a 1099 C.....must be done within three years of the deceased last filing of an Income Tax Return. If there are any monies in the estate, they can be attached. Forget " Familial Law" . It doesn't hold up in most states.
Been there, done that.

Yes Gmadarlin that's because it was your Mother's legitimate debt, therefore payable by her estate. The point to the thing about authorized users is, the account holder agrees to take on the debt of any users s/he authorizes. Anything spent by the authorized user becomes part of the account holder's debt too.

I found out after my Mothers passing didn't matter that my name was off her cards once probate is over the credit cards come after their money from the estate -the selling of the house- so we are paying on them now so the interest won't grow keep asking questions Bless you

It comes down to whether you are an authorized user on an account that has a sole "owner" who is not you, versus a co-signer of a joint account; make super sure which it is. If you're an authorized user you're not legally liable to pay, and your mom's credit is the one that gets harmed if the bill isn't paid. If you're a co-signer then you're each liable for any purchase made on that card.

Helpmom, you say that some purchases were for "solely for you"...I would think that you "should" pay for those purchases, as they were not purchases your mother made.

my 86 1/2 yr old husband signed for a card to by AC unit for our Mobile home.
The verbal agreement was not the same as the bill. Am i responsible for this as his wife?

playgrandma is wrong, my mom also has a credit card and I am an authorized user, it clearly states that an authorized user is not responsible for the credit card debt so if they try to get you to pay, tell them you are only anthorized user and not the person responsible for the debt

i am sure both of you will be responsible. If she cant afford the debt-then they will come after you. But someone will have to settle this debt. Many factors here to consider. If both of you have no assets and social security-then nothing can be done-they cannot go after social security. Other than that-they will try and get it however they can and more than likely get a judgement against you