There's quite a bit of buzz out there about Neilsen/NetRatings deciding to remove page views from its Web site traffic measurement rankings. ComputerWorld notes along with others that technologies which enable the embedding of content such as AJAX make it harder to determine what people are really looking at: the page that someone is visiting or the widgets embedded in that page. Therefore Neilsen is preferring to gauge the total time that a visitor engages a site rather than how many pages that they're looking at in a site. Forbes notes that other site measurement services are not giving up on page views just yet, and that regardless of what this may or may not mean the Neilsen/NetRatings methodology is still a "black box" unavailable for auditor scrutiny.
Neilsen has an important point about AJAX technologies making page views that much harder to substantiate as important measurement metrics, but there are other factors at play here as well. The key point that Neilsen seems to be driving towards are measurements that will be meaningful to brand advertisers used to time-based measurements via television and radio. Page views just don't compute with many of these advertisers, and perhaps rightfully so. In the highly transitory world of page views there's hardly enough engagement to provide the level of content endorsement that brand advertisters seek when paying premium rates. So for advertisers seeking "mouse potatoes" who are deeply engaged in a particular site visit time can be a particularly important metric.
The other side of this, though, is that this type of behavior tends to favor social media sites, where there is not only a mix of AJAX-embedded content but as well deep streams of comments, bookmarks and other linked content that gets users working the scroll wheel on their mouses a lot harder these days. Oftentimes the hottest content on a social media site may have dozens of weblog entries in a single page or hundreds of comments: it can take several minutes of focused reading before someone may be ready to move from one page in a social media site to another. So oftentimes total page views in social media may be comparatively low while total time engagement may be comparatively high.
None of is likely to be sweet news to search engines such as Google, where people flit through highly transitory content on their way to destination sites where they dwell over in-depth content. Contextual ads are very potent in these type of page-view environments, though - ads that are not necessarily of interest to the brand advertisers that Neilsen hopes to serve. On the other side of the coin Google's YouTube portal should be a prime beneficiary of such measurements, enabling new revenue streams for video content from brand advertisers who were never quite sold on search engine page views. There are many other details to audience measurement that Neilsen and others must take into account when coming up with meaningful representations of online behavior, but given Neilsen's desire to maintain effective relationships with media companies and advertisers putting an increasing amount of brand advertising on the Web focusing on the time people spend on a site is a strong move towards supporting destination Web site content - and towards providing social media sites with a well-deserved revenue boost.