Bill Grueskin is the Dean of Academic Affairs at Columbia University Journalism School. Prior to that, he was deputy managing editor/news for the Wall Street Journal, and before that managing editor of WSJ.com.

During the past few weeks, we’ve witnessed a growing movement to rein in, extract money from, or stop altogether the aggregators who are accused of eroding news sites’ revenues by quoting from or linking to traditional (and expensive) content.

The movement got its intellectual bona fides from U.S. Circuit Judge Richard Posner, one of the wisest bloggers anywhere, who noted the dismal state of newspapers’ finances and suggested it might be necessary to start “expanding copyright law to bar online access to copyrighted materials without the copyright holder’s consent, or to bar linking to or paraphrasing copyrighted materials without the copyright holder’s consent.” In other words, if you quote, you pay, and if you link, you pay.

Joining the fray was Connie Schultz, a columnist at the Cleveland Plain Dealer, who went even further, endorsing a proposal to impose a 24-hour ban on profiting from links from news sites by aggregators, and demand a revenue share from advertising on others relying on news sites’ original reporting.

This was all too much for corporate hagiographer Jeff Jarvis, who fulminated on his blog that Schultz, a U.S. senator’s wife, “should be registered as a lobbyist” and then queried the senator, Sherrod Brown, as to whether he would recuse himself from voting on related legislation. (For those with a strong stomach, Clint Hendler at Columbia Journalism Review does a fine job on the play-by-play.)

It all makes for entertaining reading, except it misses the larger point. Which is this: What good is Web traffic anyway when the online advertising model is so badly broken?

We hear a lot about the death of journalism these days, but much of the crisis really amounts to the death of advertising, or at least advertising as we knew it.  This is a huge problem facing journalism (and more generally, media), and it’s easy to get caught up in debates over linking and copyright while missing the bigger issue.

It’s troubling that, even as traffic to news sites is growing, their once-lucrative home pages and article pages are displaying house ads or remnant ads with CPMs of no more than $1. At that rate, even a link from Drudge, which could refer 500,000 page views, generates only $500.  That sum covers the server costs and not a great deal more. It certainly doesn’t pay for the salary and benefits of the reporter and editors who worked on the story. And it’s not just a function of this bad economic cycle.

We see the same dynamic even at a site as large as nytimes.com. Zachary Seward, an astute blogger at the Nieman Journalism Lab, recently noted the huge surge of 9 million uniques in two hours to the New York Times’ site, thanks to a direct link from Yahoo’s home page. But the link didn’t generate a great deal of revenue; similarly, a Yahoo-related surge to the Wichita Eagle Beacon last February sent 3 million uniques to the paper’s site but provided only a few thousand dollars in incremental ad sales.

The other day, paidcontent.org cited a poll by Harris Interactive Inc., which reports that Internet banner ads – which comprise the bulk of the advertising that appears on news sites – were deemed largely worthless by the 2,500-plus Americans queried last month. The group found TV ads the most valuable for consumers making decisions about what products to buy, followed in effectiveness by newspaper and web-search ads. Online banner ads were seen as “most helpful” by an infinitesimal 1 percent of the group, while 46 percent said those banners were precisely the ads they disregarded the most.

In other words, even if it’s true that aggregators are siphoning off users from news sites (and it’s pretty clear that they refer traffic to sites as well as drain traffic from them), does it make a big difference in a world of $1 CPMs? Yes, it’s hard on the ego to watch another site get credit for your hard work, but is it really hurting the bottom line?

In a recent CJR article, Peter Osnos looks at how Huffington Post garnered a ton of traffic last February from Sports Illustrated’s scoop on Alex Rodriguez’s steroid use, even though SI.com was where the story broke. Osnos writes, “As long as the value of advertising on the Web is measured by the number of visitors a site receives, driving those numbers is critical.”

Actually, that might not be true any longer. The value of advertising online ought to be measured more by engagement than by sheer numbers, that is, more by metrics like time spent or page views per user than by the sheer number of people coming to the site, many of whom may not assign any value to the journalists who generated the content.

Indeed, as we hear more about “freemium” (mixed paid and free) models, publishers and editors ought to be thinking about who their most engaged readers are and what characteristics they share.  When I was at WSJ.com, I remember looking for the day of the year that had the highest time-spent and view-per-user stats. (Can you guess the day? Answer is at the end of this article.*) Those readers constituted a base of the people who would read the site virtually anytime, anywhere – in other words, precisely the people who would always renew, and at higher and higher rates.

News sites are in a heap of trouble these days, and it’s tempting to see aggregators, bloggers and other third-party sites as the villains. It’s also possible to see them as the saviors, for the users they can send to a site.

In fact, until publishers and editors figure out how to identify and engage their readers and make money off of that traffic, aggregators are more a distraction from the real crisis than the cause of it.

* The top-engagement day was Christmas. Those are special readers who sneak up to their study to read WSJ.com while their kids are opening gifts in the living room. God bless ‘em.