Here’s the story from the Times:
“Since we launched TimesSelect in 2005, the online landscape has altered significantly. Readers increasingly find news through search, as well as through social networks, blogs and other online sources. In light of this shift, we believe offering unfettered access to New York Times reporting and analysis best serves the interest of our readers, our brand and the long-term vitality of our journalism. We encourage everyone to read our news and opinion – as well as share it, link to it and comment on it.”
Also, according to their podcast , only one-third of those who signed up for the TimesSelect were actually paying.
UPDATE: Dan Gillmor has an excellent blog post about why this is such a great move. Here’s his take on the opening of the Times’ archive:
Presumably, each article will have a perma-link. If so, watch what happens. The Times’ stories — many of which are definitive moments of journalism — will become the de facto primary sources for people around the Web, and around the world. On topic after topic, the Times story (or stories) will move near or to the top of the search engine rankings. They will become more valuable for keyword and other advertising once people click through to the actual stories.