Coming here to let people know about your personal item you have listed on ebay (Enya 4C somebody had sitting in his shop for years) is not spam. That person is not running a commercial enterprise.
The poster posting to tell us to go to his businesses website to buy the video about cutting foam wings is spam. He is passing it off as a business, he pays google to place ads for him in related google searches. So his post is considered an unsolicited commercial advertisement. Another word for that is SPAM. You click on his link, find out it's only available on VHS and he whines when you tell him it's useless to you.