Great idea to write about/give a strategy for this, I've never seen this addressed before. What's unique about these sites is how rarely they actually do anything - they tend to be viral jokes, but they don't function towards any sort of business goal besides a nice add to the design portfolio. Part of that is cause that's simply required to get these to go viral - any sort of business mention causes it to crash and burn. But minimalism and a rough themeatic connection can serve to help, but we really haven't seen it consistently done other than for the purposes of a very cool thing to add to the resume, which can indirectly make a few people some coin.