re. Has anyone ever bought anything on the strength of a web advert?
Unfortunately, while I don't have solid proof (figures), the statistics go against your personal experience (and mine). And I very much doubt the marketing / ad business would be able to lie about those figures on such a massive, world scale to fool those that pay dearly to have their products / services adertised year, after year after year. Sadly, marketing, adverts, do work. Even more sad that they do work, apparently on those that believe the ads don't work on them.