Nicco and EchoDitto have been at pains to emphasize it as a personal choice and one not related to the firm's business, but presumably there's a little more heat in this story -- first reported by Hotline On Call in an interesting piece on the McCain campaign's apparent emphasis on web campaigning for '08* -- than either anticipated.
* - Dean in '04 vaulted Internet campaigning into the spotlight, but McCain in '00 was a major pioneer of a less mature medium.