From Investor's Business Daily: Tech Center Exec Q & A:
"IBD: Why is adding a special domain name important in identifying whether an e-mail message is wanted or not?
Crocker: Existing 'reputation' based e-mail screening systems are based on very low-level addressing numbers that say where a server is attached to the Internet, rather than what organization is sending the message. DKIM will identify the sender."
I work for an ESP (that's shorthand for email service provider). I've been following DKIM and added my 2 cents here and there on the IETF mailing list for DKIM. I hope Dave was misquoted. DKIM could identify the sender, but it could also not. It can identify an Author, or an Author's domain, or something else completely. This is because DKIM isn't tied to any previous email identity. It can create an entirely new one.
It will be interesting to see what Terry Zink comes up with when he continues his series on Authentication.