I tried to find ads in Amazon... And found none. I get nothing. Only the "(not)similar products on other websites" which is a total miss most of the time. I doubt this is what the article is referring.
Do a search for the word "sponsored" on most any pages. There are almost always sponsored links and sometimes sponsored products as well.
Can't find any at all on Amazon.co.uk. Pics or it didn't happen?
I would hope so - I've never purchased a thing off twitter...
You probably never bought anything out of an banner, and that's what the article is taking about.