This morning, New York Times (NYSE:NYT) announced that tollbooths will be going up in certain parts of its popular website. Come Monday, it will be limiting access to its choice columnists to those paying $49.95 a year. The Times Select digital subscription won't interfere with the rest of the popular news site, which will remain free of charge.

Premium content can be a tricky thing in cyberspace. It's pretty much expected when it comes to financial-services content such as (NASDAQ:TSCM) with its RealMoney portal and Morningstar's (NASDAQ:MORN) research reports. Our own site's content is free, save for our premium research newsletters.

However, it gets to be more of a challenge for general news sites. Shares of Salon (OTC BB: SALN) have traded in the pennies for years as the company tries to gain traction with its subscription model despite its compelling collection of columnists.

It's easy to see why the publisher is going this route. Yesterday, media giants Knight Ridder (NYSE:KRI) and Gannett (NYSE:GCI) warned of sluggish ad sales in the newspaper business. If charging for its great columnists online drives subscriptions to the company's flagship newspaper from freeloaders who figured they could just click away with ink-free hands, it's a fair strategy.

Unfortunately, it's also a naive strategy. Newspapers and broadcasters have been bellyaching about their ad sales for some time now. Meanwhile, Google (NASDAQ:GOOG) -- a company that relies on ads for 99% of its revenue -- keeps reporting record results. It's obvious that many marketers are earmarking a larger chunk of their ad budgets online. That's why a digital subscription model may sting New York Times as its page views dip and the wired news-hungry go to nibble at the free content trough down the road.

Yes, most of the site remains free. Its news and reviews will continue to be dispensed gratis by news aggregators like Google. However, the proprietary columns will draw thinner crowds online, and that will limit the viral splendor of a truly great piece making the rounds among connected friends (like Dan Barry's brilliantly written piece "The Corpse on Union Street" earlier this month).

New York Times is also including limited archive access for its new Times Select subscribers. That's something readers could have purchased piecemeal in the past, and it definitely adds value to those looking to dig up dated content. Yet with Internet-based advertising becoming so much more important with every passing news day, does the paper know what it may be giving up along the way to a model that looks good on paper?

Who would have thought that digital ink could smear?

Longtime Fool contributor Rick Munarriz thinks that Barry's column is the definitive piece on the tragedy in New Orleans. He does not own shares in any of the companies mentioned in this story. T he Fool has an ironclad disclosure policy. Rick is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early.