The paywalled JSTOR service is set to offer 70 of its 1,400 journals for free, albeit hedged around with restrictions. But…

“if it works out, JSTOR says, it could expand the program to most or nearly all of the database” […] says it has been turning people away from seeing an article 150 million times a year”

The service already offers public-domain articles (before 1923) for free.