Am I Obligated to Advertise for Sellers?

I am not talking about DT members or people who show products on their blogs in exchange for product, just to be clear here.

A few days ago, I got a scathing email from a person from whom I purchased some very small and inexpensive embellishments on ebay. To be honest I buy things and very shortly thereafter cannot even remember where I bought them.

Weeks ago, I posted a card using one of her embellishments on something I made. I made no mention of where I purchased the very tiny item worth a few cents and no link so others could buy from her. For my total of $4 purchase (for 60 mini items made of paper and not original in any way) she apparently assumed I would be forced to do free advertising on my blog whenever I used her product. She was horribly upset that I did not link her site on my blog.

Are people obligated to start blogs so that anything they buy and use can be advertised for the seller? She implied that every time I punch a flower, for example, and use it on a card, I am obligated to link to the seller of the punch and make a pitch for their product. Often I include a list of sources simply for ease for other cardmakers to see the source. I do not feel obligated to earn my use of the purchased product by advertising it for the seller.

I don't think it should be an obligation every time I purchase something to then use it and post it on my blog including a link. Should I really have to keep a notebook with the source of every button, piece of yarn, and such and advertise it for someone if I use it? What do you think? If you want, email me and I will combine the responses to let readers know what others think of this expectation.