These bikes aren't that overpriced, as long as they have decent quality parts -- although that's a bit of a mystery since they don't really mention what brand/model most of the components are, which seems suspicious. Anyways, the single speed is $600, and $600 isn't much more than the bare minimum you can spend for a new bike that's of reasonable quality (probably $400-ish).
Furthermore, they are a small company with character, and many people like to support such companies instead of further feeding the massive, bland, corporate manufacturers. In a way, it's sort of similar to buying a Mac (and I mean that in a good way).
It's also mind-boggling how sheltered some people here are. You guys apparently have no clue that bikes are more than mere toys/sporting goods, and can actually replace a car in some urban areas. In that context, carbon fiber is silly, and $600-$1200 is absolutely nothing when the average new car costs $28000, plus interest, gas, insurance, lack of exercise, harming everyone's lungs, fouling up runoff water, dominating the landscape, dividing neighborhoods, 40000 deaths per year in the US (1+ million worldwide), resource wars, oil spills, habitat destruction... how absurd is that $600 bike now?
And the mention of San Fransisco leads to "i love you" being thrown around nonchalantly? Really classy.