Kami Huyse at Communication Overtones makes some interesting points about "meaningful measures of the relationships a site or blog is building," see her post ("Eight Meaningful Measures of Social Media").
I second her view that page views is crude and uninformative. The reason it is used is because it's an easy number to get, not because it's a particularly meaningful measurement. Social media is about relationships. Measuring social media with page views is like measuring a friendship by the number of phone calls. It says something, but not much. (With some exceptions: "Hey, you don't return my calls anymore?")
(By the way, here's the best presentation I've seen of why page views are dead: "How RSS Kills Banner Ads" a great little tutorial movie from The Ronin Marketeer on how RSS feeds are making banner ads obsolete.)
Let's think big picture for a minute... We can anticipate that social media will continue to expand in complexity of interactions, as technology allows. Where is it going? We can bet that AJAX is only the tip of the iceberg when it comes to tricky things to measure. (See Mike Shields' Mediaweek article "Ajax Puts Web Ad Sales in Peril")
Here's a prediction. I suggest that, as technology develops, social media will get richer and more complex in the nature of the interactions it allows between people until those interactions are at least as rich and complex as the real-life social interactions people are already comfortable with. People interact most meaningfully when they are face to face, talking to each other, like sitting around a table at a meeting or a meal. So our eventual measurement target will be to measure relationships with that level of interactive complexity: face-to-face, sitting around a table. Imagine interactive video blogging, how are we going to measure that?