There's also NameCoin (http://dot-bit.org/ http://dot-bit.org/) I don't think it has any chance of being widely adopted in its current incarnation because of t

There's also NameCoin (http://dot-bit.org/ http://dot-bit.org/) I don't think it has any chance of being widely adopted in its current incarnation because of two major flaws: 1. The early adopter advantage is too high (the designers took steps to limit this, but not enough.) 2. Renewal is free (encourages squatting.) And there are other missed opportunities. A built-in auction system would be nice, as would a mechanism for registering a "tld" and inviting public registration of subdomains. Still, I reckon they got the basic idea right - decentralised registry of domains, using well-tested (thanks to bitcoin) cryptographic algorithms.