So let's say you have an idea for a new kind of photo site. You want a place where professionals gather to display and sell genuine photo art. This isn't going to be another Flickr; this is all high-end stuff.
You spare no expense on the rollout. You invest in a gorgeous design, both elegant and functional. You grab photoartgallery.com as your domain name. Descriptive, but not too long to type. Everything's going great. You don't even need to pay for product identity development. And as a result, you nickname your site after flatulence.