I used to work as a developer on a large sneaker site based in the UK (Crooked Tongues). Before then I had just thought of sneakers as something you wear. One of the guys I worked with was heavily into it and since we would get a (heavy) discount he'd suggest pairs to me I should buy purely as an investment. I think the best return I had was nearly quadrupling my money on a pair of Air Jordan 5s.
One of the last projects I worked on at the agency was a book of rare and collectables [1] - I think at one point we had the equivalent of half a million dollars sat behind my desk (the large yellow box in the middle is the Nike "Air Mag" Marty Mc Fly sneaker they mention in the article) [2]. After all this I understood a hell of a lot more that there's money in anything when enough people want it. Sounds obvious, but I didn't fully appreciate it until then. That and the power of marketing to create value out of thin air.
[1] http://www.thamesandhudsonusa.com/books/sneakers-the-complet...