This was bound to happen--it was only a matter of time. Details on the exact plan are scarce, but expect a lot of changes in the coming year, with lots of chatter from media outlets.
It's gonna be hard to go from free to a pay wall, but it might be a good deal to pay a flat yearly fee for access if it's necessary. I know a lot of people will try to bypass the site--hey, it's aggregated everywhere! Who needs it, when you've got Google--but the Times will make sure that they aren't hijacked by other outlets.
They'll make some money, as agencies and organizations will pay for access, and some people might splurge for a print subscription, which guarantees a free web site.
There are only a few newspaper websites that charge for access, a few of them local dailies. The Wall Street Journal has a pay wall, also bypassed with a print subscription, but that works because that paper primarily serves a business audience, and readers tend to have access through their jobs. The New York Times is the most visited newspaper site in the country, with over 17 million viewers a month, according to Nielsen online. This approach, compared to sites like the Journal, is meant to keep much of their audience and ad revenue. The fear is that those who receive links to the site will now stop, or spend less time on the site, because of the pay wall. Although the newspaper has said they do not want to lose the prestige that goes along with such high numbers, it was a move they had to take.