Faced with the rapidly changing dynamics of the Web, including the fact that new forms of Web programming have drastically changed the definition of "page," comScore Networks - which just last week declared MySpace the page view leader over perennial champion Yahoo - quietly announced today it is changing the way it assesses pages, and intends to roll out this new system in 2007.

The change, once it comes, could immediately impact the standings of comScore's Top 50 Web properties, which are assessed primarily by number of page views, and secondarily by number of unique visitors. Since Yahoo rolled out programming changes to its home page earlier this year, its page view counts have decreased by 5% or more, according to comScore.

But Yahoo's unique visitor count has not declined, despite reports that MySpace had "dethroned" Yahoo. That fact is leading to an amplification of a months-old debate over whether a "page view" -- essentially, the transmission of content in response to an HTTP request with a single URL -- is no longer an adequate metric for judging relative readership.

In revised home pages, such as Yahoo's which uses Asynchronous JavaScript (AJAX), users can change the content of portions of the interior of the page without forcing a refresh, thus reducing consumed bandwidth and improving efficiency.

MySpace has not yet adopted such an approach, and may prefer not to in the face of what similar changes have done to Yahoo's and CNET's bragging ability. On the other hand, MySpace might consider such changes if the rest of the industry were willing to abandon old-style page views as a common metric.

ComScore's announcement today came by way of substantiating its recent reports of MySpace usage surges, citing an increase in visitation among college-age users. But further down the scroll came this acknowledgement:

"The recent decline reported by comScore in Yahoo! Sites page views underscores another emerging issue in the Web metrics measurement industry. New technologies such as AJAX - which enable real-time site updates without needing to refresh a page - are impacting the relevance of page views as an accurate measure of the intensity of consumers' Internet usage."

The announcement then quoted comScore President and CEO Dr. Magid Abraham as saying, "The Internet experience today is much more dynamic thanks to Web 2.0 technologies like AJAX. While page views will not altogether cease to be a relevant measure of a site's value, it's clear that there is an increasing need to consider page views alongside newer, more relevant measures. comScore is proud to continue carrying the torch as an industry innovator with the development of a new suite of metrics that will effectively address the Web 2.0 landscape by including enhanced measures of user engagement and advertising exposure."

Earlier in the statement, Dr. Abraham noted other analytics firms still show Yahoo with both a page view lead and a unique visitor lead over MySpace. comScore's apparent differences, he said however, were due to measuring college and university users alongside work and home users, implying that competitors may not be so balanced in their approach. If college users were omitted from comScore's picture, Yahoo would have a 2% lead in page views.

ComScore’s announcement confirmed early numbers pursuant to its upcoming official release of its “Top 50” Web properties for November, preliminary figures for which were leaked through to financial analysts last week. Fox Interactive Media, the parent of MySpace, leads the collective page view category with 39.5 billion page views, 98% of which belong to MySpace. That represents a 3.8% lead over Yahoo with 38.0 billion page views. (CORRECTION: We’ve been getting this figure wrong ourselves, as Andrew Lipsman of comScore told us. These page view numbers are in billions, as CNN has been correctly reporting, and others have been changing to millions.)

A full 8% of all page views, comScore says, are consumed by college users. If the firm were to quantify Yahoo's page view decline just among college users as a percentage, it could conceivably apply that figure to MySpace's numbers to figure out how an AJAX-like change could impact the standings of the world's largest social networking site.