Some amount of innovation seems inevitable for any successful startup. Most of us could build a site in a weekend that does image sharing, but it would take some serious innovation to scale the site up to a billion users without blowing the bank on infrastructure. Doing the same thing people have been doing, but at 1/10 the cost is clearly innovative.

Whether its scale, raw idea, business model, speed, quality, or whatever; there has to be something new to get any significant traction. Are all types of innovation equal? Of course not, but all types provide some sort of value. Throw open source into the mix and you start to see the network effect in play where even "useless idea" startups provide value (although the creators may not get much return on it) in the form of assisting more useful ideas come to fruition.