Spare parts, for one. BART for example is dependent on old computer parts from Ebay to keep the Bay Area's main mass transit system running: https://news.ycombinator.com/item?id=32884814

Speaking as a customer, it's slow, annoying, and makes the shopping experience there miserable. If you innovate in that software space, you might be able to make a significant impact on the trade of certified exotic wood and maybe even save a few species of tree.