Examples of New-school Online Retailers?

Retailers like woot.com, 200 nipples, and Threadless are changing the way that online retail works; instead of focusing strictly on a store of items, they use time sensitivity to drive sales. While sitting in jury duty yesterday, I had an idea that might be amenable to a similar style of online retail store. Before I dive in though, I'd like to look at more examples of this style of retail and hear what the community here thinks of it. My questions are two: 1) What stores are changing the way retail is done on the internet via limited edition, time-sensitive sales? and 2) What do you think about this model of retail sales?