• by Erik Sass  @eriksass1, September 27, 2011

The list of newspapers charging readers for access to online content is growing longer. The Baltimore Sun will begin selling digital subscriptions to its Web site on Oct. 10. This will make the Sun the first newspaper owned by Tribune Co. to erect an online pay wall -- possibly foreshadowing similar moves at other big Tribune papers, including The Chicago Tribune and Los Angeles Times.

Like some other big newspapers charging for online content, the Sun will combine free and paid access. Readers can see 15 pages per month for free, after which they will be asked to buy a digital subscription.

For the first month, the newspaper is offering a special introductory price of 99 cents for the first four weeks. Then, subscriptions will cost $2.49 a week or $49.99 for 26 weeks. Unlike some other papers, print subscribers will also be asked to buy a digital subscription, but at a special reduced rate of 75 cents per week or $29.99 a year.

According to the newspaper, in August 2011, The Baltimore Sun Web site attracted 4.8 million unique visitors, who generated a record 52 million page views.

While substantial, these numbers are quite a bit lower than The New York Times Web site, which erected a pay wall in March of this year. Before the pay wall went up, the NYT Web site attracted roughly 30 million readers per month, according to comScore. Of these, about 4.5 million qualified as "heavy users" who were good candidates for digital subscriptions.

Under the NYT digital subscription plan, visitors can view up to 20 articles per month for free on the site. After reaching this limit, they are required to choose one of three monthly subscription plans for further access.

Some heavy readers also received special, free unlimited access sponsored by Lincoln, and more recently, Polo Ralph Lauren has sponsored free access for iPad readers to five sections -- Fashion & Style, Travel, Home & Garden, T Magazine, and Sports -- during September.