Jonathan Goodyear‘s ASPSOFT just announced Email2Face, a public database mapping email addresses to photos. This strikes me as a good and useful idea. If it gets some traction, it would be nice to have an email client plugin to automatically retrieve them.
What I would really like to see is something with a similar results, but rather than be a project from one company, instead be open, scalable, and RESTful; perhaps some mapping from email address to web site containing information about the owner of the address. For example, agree that for email@example.com, information will be a http://bbb.com/email/aaa/ and from there have links to specific kinds of information, such as… a face photo.