10. DarkWallet: Untraceable bitcoin wallets - this can be bad obstacle for mass adoption I think. Mass media and people who think that bitcoin is just tool
created for hackers for criminals would have a solid argument when this service will launch...
Why would it be a bad obstacle? Most of the public already thinks bitcoin is untraceable or anonymous so this wouldn't be any different. I don't think darkwallet will become mainstream and only have a niche use amongst criminals and super libertarians but it's there if you want to use it.