Its a Lot harder to include tracking at render time if you arent your own site admin. I am talking about hosted services - they will be the ones to struggle (wordpress.com, blogspot etc)
Google analytics works at server side and most scripts include it at this level - the switch for devs to server side tracking will be super easy but not for most people. Server trackign used ot be all there was until somehtign called urchin came along. I suspect that there will be a requirement for a session id for multi page sessions. Maybe I am being paranoid but I am juz making sure I am ready for anything.