The New York Times has just changed their archival policy so that all links we've used in the bIPlog that are more than 30 days old will redirect to a page requesting that you purchase the article for $2.95. Links have worked before now, even though articles were months or years old.
Vin Crosbie, President of Digital Deliverance, talked last week at the JSchool about news online, and the mechanisms and logic that publishers use to charge for certain kinds of content (presentations here). Regarding the NY Times, he mentioned them in a survey of similar publishers like the Wall Street Journal and the Financial Times. The publisher of the WSJ said "don't charge", it's not worth it, as it took 6 years to get them from 60k subscribers to 600k, and only because of their unique position as a premiere content source for market news have they even come this far. The FT.com said that charging has been disasterous for them. The NY Times told Crosbie they had no plans to charge for any more of their content than they did then. However, that publisher is no longer at the Times, so my guess is that the new publisher is trying to figure out how to make more from their archives.
But Crosbie said that these publishers had generally found that charging drastically reduced their page views. As an example, in the case of the Irish Times, which before they started charging for the online paper had 1.25 million unique users per day, and 25 million page views, experienced a dramatic reduction of visitors to 7000 people signed up with 1.7 million page views. Their banner ads collapsed.
The conclusion is that ads drop so much, and it harms information flows and your brand for the future, that if you want future users, and to keep current users from going elsewhere, the content must be free.
Jenny Levine notes this: "Just a friendly reminder that pretty much every library has some type of access to the NY Times archive, and many also provide remote access to it via a link from their web site. It's not ideal for Google searching or the "opportunity to assert authority," but if you need a specific article, you can get it from your local library for free."