The Wichita Eagle’s Kansas.com was the 15th-most-visited American newspaper site in February, according to Nielsen Online. That’s remarkable, considering that the Eagle has never previously cracked the top 30.

What happened? A prominent link on Yahoo’s front page February 13 caused an astounding wave of traffic to the Eagle’s 389-word story about a student who caught an embarrassing error on the state writing test. (An essay prompt referred to “the omission of greenhouse gases,” enough to emit a scream from any orthographer.)

In a single afternoon, the Yahoo link sent roughly 3 million unique visitors to Kansas.com — which typically draws no more than 800,000 uniques per month, Nick Jungman, the site’s deputy editor for interactive news, told me today. That was enough to send the Eagle’s traffic numbers zooming past its rival three hours to the northeast, The Kansas City Star.

“All of a sudden,” he said, “we were just flooded.”

But while it was a banner day for the Eagle, it wasn’t particularly outstanding for the site’s banner advertising. The huge wave of Yahoo traffic generated just “a few thousand dollars” in extra revenue, according to Jungman.

Like most commercial websites, Kansas.com runs dirt-cheap remnant advertising when its traffic exceeds expectations in order to fill the space without wasting local advertisers’ money. For a local news site that occasionally attracts national attention, the spikes are nearly impossible to significantly monetize. One study found the average CPM for a news sites’ remnant advertising in the fourth quarter of 2008 was $0.34 — that is, for every 1,000 people who saw an ad, the site was paid 34 cents.

The Eagle’s experience is a reminder of how wide a gulf sits between the high-end advertising on highly trafficked blog networks like Gawker Media and the scrap heap that often runs on local blogs and news sites. I wonder if McClatchy, owner of the Eagle and 29 other daily newspapers, could take advantage of its own network. Surely, at least once a week, a McClatchy news site experiences unusually heavy traffic. What if the company’s ad servers were agile enough to direct some sort of national — and more lucrative — ad sale to whichever site just hit the front page of Digg?

Despite the missed revenue, Jungman said the traffic was valuable because it brought an energy boost to the newsroom and could have put the newspaper, which doesn’t circulate far beyond Wichita, on the radar of “a few people who might really like our site but didn’t know we exist.” He said the Eagle’s servers, which are handled by McClatchy, held up fine.

Jungman said the Eagle regularly reaches out to Yahoo and other popular sites “when we have some interesting, fun story that might be of interest to them.” For the test article, interactive content editor Lori O’Toole Buselt sent an email to Yahoo News along with a picture of the beaming 17-year-old who caught the spelling error. Another piece on the site last month — a story on the state’s plan to delay income-tax refunds — picked up half a million visitors after catching the attention of sites like the Drudge Report and Perez Hilton, who wrote a quick blog post entitled, “The State of Kansas Is Effed!”

“I’m not above, on occasion, sending an email to Drudge,” Jungman said.

(Perhaps ironically, at this writing, the link to the income-tax story is broken. So someone searching for “kansas delay tax returns wichita eagle” would instead be directed to all the many blog posts commenting on the story. Or they could check out the 26 web sites that appear to have copied-and-pasted the entire Eagle story onto their own servers.)

All told, Jungman said the Eagle had 4.97 million unique visitors in February. Nielsen Online, which is widely criticized for the inaccuracy of its statistics but generally reliable for relative measurements, put the Eagle’s traffic at 2.78 million uniques. Compete.com says 1.94 million. Quantcast, 4.2 million.

According to the Eagle’s servers, they eclipsed the site’s previous high of 4.5 million uniques in May 2007, when a tornado wiped out the town of Greensburg, Kansas. “That was mostly people looking at our photos of the destruction,” Jungman said.