[ef4]

Yes, usability is the problem. But none of these proposed solutions manage to actually solve the usability problem without throwing out the security.

We really do need to let users manage trust, because trust is a rich concept. And humans are actually really good at trust, because we've been thriving and competing with each other in complex social situations for a long time.

The trick is finding ways to recruit people's evolved trust behaviors into an electronic context. That is, can we build meaningful webs of trust through repeated social interactions, just like in real life?

So it's not the mail client vendors who are best positioned to solve the problem, it's the social networks.

(Whether they want to solve the problem is a separate question.)