[ What backs gold? Gold only has value because people desire it for various reasons such as using it as a conductor, jewelry, beauty (that does not corrode) and extreme maleability,
I think you pretty much answered your own question here.
There is no intrinsic value in the USD beyond the fact it is massively used in trade and traders
There are some people who like backed money (money that has a applications outside of its use as currency, like gold/silver) and some people who are ok with unbacked fiat (like USD), It was probably a mistake for me to list USD as one of things that could be used to back an electronic currency. The point I was trying to make was that NameCoin has the features of Bitcoin plus it has utility, that may make it acceptable to people who wouldn't be interested bitcoin.