Measuring the danger of being impersonated is very difficult. It depends on how creative the attacker is and the social circumstances of the victim. Further, the victim can easily be unaware of the danger until they get bitten once.
This is going to be a serious issue for Posterous if they ever go mainstream. Opt-in authentication schemes won't be enough to prevent scores of naive people from being humiliated the first time, particularly teenagers.
This is going to be a serious issue for Posterous if they ever go mainstream. Opt-in authentication schemes won't be enough to prevent scores of naive people from being humiliated the first time, particularly teenagers.