Our favorite inventor and bloggerfather Ev Williams has an excellent post about traffic, page views, how the old web metrix don't work re: the new web flow of conversation, etc. Because we now connect and communicate BEYOND the textual hyperlink, page views aren't what they used to be. Poor site design that boost page views by site elements loading individually, those visiting through widgets and RSS feeds--and I'll add the incredible number of referrers coming through misleading or irrelevant search engine results--these are just some of the reasons why a page view isn't a page view isn't a page view.
But Ajax is only part of the reason pageviews are obsolete. Another one is RSS. About half the readers of this blog do so via RSS. I can know how many subscribers I have to my feed, thanks to Feedburner. And I can know how many times my feed is downloaded, if I wanted to dig into my server logs. But I don't get to count pageviews for every view in Google Reader or Bloglines or LiveJournal or anywhere else I'm syndicated.
Go read it all.