A couple of years ago it seems just about every newspaper threw in the towel and lowered the firewall to content. The supposition was simple: Traffic would grow much faster that way --- along would come revenue from display advertising --- than if the firewall remained and the subscription revenue crept along.
The risk of harming the newspaper franchise was calculated at the time and the decision was that it was better to move forward and grow audience than limp forward with a smaller one. Besides, everyone noted, others were offering content free, so it was necessary to jump in.
Of course, much has changed in the newspaper business since then, particularly the economic model of advertising-supported news companies. Lately there have been some calls to look again at the all-is-free model and try to charge. There are some clear technical hurdles (firewalls are relatively easy to scale) and some major cultural ones, but in this essay for Online Journalism Review, Gerry Storch of Outlook.com lays out the case.
He argues that it's necessary to discard the print model and create niche powerhouses online. It's an interesting read.