Nielsen/NetRatings has decided that the total amount of time that consumers spend on a website is more important than the number of page views or unique visitors that the site has.

According to The Washington Post, the new rankings favor Yahoo! (NASDAQ: YHOO), Time Warner's (NYSE: TWX) AOL, and Microsoft's (NASDAQ: MSFT) MSN to some extent because they have substantial e-mail and instant messaging traffic. AOL moves to the head of the list because it had 25 billion minutes spent on its sites in the U.S. during May. Google (NASDAQ: GOOG) is poor at 7 billion minutes.

But the new ratings system is substantially flawed if what you really care about is how much revenue a site generates. Time spent on instant messaging is not like time spent on search, which is also not like time spent on watching a video. AOL may have more time spent than Google, but the search engine's advertising model is based on targeted text ads attached to search results. It is hard to argue with the AdSense model since it generates more revenue than any competing system.

AOL's "minutes" were 3.5 times Google's minutes during May, but a metric that has nothing to do with revenue creation is not much of a metric at all.

Douglas A. McIntyre is a partner at 24/7 Wall St.

In the old days of the internet, (a week ago), every time a viewer wanted to see new content he clicked on a link that took him to a new page. In those days, advertisers were charged for each new page view with their ad on it.

With new technology, though, page views aren't a good measure of ad distribution. Now, while a viewer stays on a single page, perhaps watching a video, other parts of the page can be changed and refreshed without reloading the page. For example, on this page you'll probably notice some ads changing as you read this post, although it only counts as one page view.

That's the reasoning behind Nielsen's NetRatings change from page views to measuring the time readers spend on a web page. Their ratings are used as a basis for ad revenues, so the impact of such a change could be huge.

The change comes as welcome news to sites such as (ahem) AOL (BloggingStocks is owned by AOL, a unit of Time Warner Inc. NYSE: TWX), the internet leader with 25 billion minutes of viewership per month (read slowly, please. Ka-ching!)

Google Inc. (NASDAQ: GOOG), the leader in page views, is only fifth in time spent, behind AOL, Yahoo! Inc. (NASDAQ: YHOO), MSN/Windows Live (Microsoft Corp. NASDAQ: MSFT), and Fox interactive (News Corp, NYSE: NWS). This despite having the most unique visitors, 110.2 million, compared to AOL's 91.6 million.

As Google ratchets up its YouTube advertising program, though, it stands to make a killing. The average YouTube user spends a whopping 46 seconds viewing time per page.

If you wanted to do us a favor, you could keep BloggingStocks up on your browser every night while you sleep. Hey boss, can you spell BONUS?