Why should I use OpenID?
art_wells: To re-emphasize/clarify previous statements, OpenID doesn't require visitors to know about OpenID.  A website can offer a registration/login process that requires nothing more than the visitor's AIM screen name, or livejournal account.  (See example http://nshrine.com/u/registerhere.html )This not only eases the yet-another-name-and-password problem, but it also allows services complimentary to existing services to ease information sharing.  For instance, OpenSocial functionality will be a breeze if accounts are already using an OpenSocial provider's OpenID.