This may well turn out to be not so-good for the adult industry IMHO.
I can well imagine all 'public' computer terminals (schools, colleges, universities, libraries, government offices and departments) and nearly all businesses doing a blanket ban on the .xxx. Then of course you have the ISP's some of whom could well 'blanket ban' any links to .xxx, this is without the likes of Microsoft who again could decide to require special authentication to access .xxx such as the verification through credit card information.
So although the supporters of .xxx may think this is a cart blanche money making opportunity I think it may well prove to be if not a poisoned challace then at least a 'tainted' challace.