This answer by a user has an interesting editing history.
- He wrote a promotional answer (and 5 others)
- Those answers were flagged as spam and they were removed.
- He changed this particular answer to show a way to solve the problem without his product first. In the second part he promoted his product and disclosed his affiliation with it. At that time the answer was still in deleted state.
- He changed the answer again and removed the disclosure and replaced the promotion with a video "showing the user a solution" (quoted from edit summary). This video was created and uploaded by his company.
- His post was undeleted by a mod.
In my opinion this answer is still spam. It shouldn't really matter how many layers of youtube videos and blog posts someone adds to obfuscate the promotional intention. Even if the product is not mentioned a link can be promotional.
However, since a mod explicitly undeleted the answer I am not sure if I am correct on this one.