creating a website where you can store $10, send it to me, and then let me withdraw it, is a 5 year felony in california. that's even when the site is complying with all anti-money-laundering and know-your-customer regulation that could be argued for because of terrorism. it's purely a licensing issue.
bitcoin's influence probably won't significantly grow until people find legal workarounds/ways to comply (of which there are plenty, but likely implementing them takes someone committed at least a year), or something happens that makes enforcement of the law unlikely.
i personally know of a sizable number of bitcoin startups with working/finished software and a great marketing strategy, that gave up in the face of financial regulation and threatened jail time.