Paywalls kill off critical interaction with the wider blogosphere and reduce readership drastically. I can see why media moguls might want the paywalls as some kind of replacement for all the power and money they have lost over the last decade. But I fear that the moment has passed.But it occurs to me that, as someone who routinely blogs about science, I'm actually already working the way that more general news sites like the Dish might in a paywall-heavy environment – I frequently link to pages that contain only an abstract of the source article and a link via which you can pay some ridiculous figure for one-time access. The scientific journals to which I link are far more expensive than the New York Times will ever be. Yet I, and a lot of much more successful science-focused bloggers, are doing OK, and people are learning about new scientific results through our (mostly their) writing, probably mostly without ever clicking through for the original articles. That wouldn't work for the New York Times.
So why does it (kinda, sorta) work for scientific journals? (1) Maybe most of my readers are academics, with institutional subscriptions to carry them past those links with the [$a] tags. (2) Maybe those of my readers who don't have institutional subscriptions don't count as lost revenue for the journals, because they're people who would never buy a copy of Systematic Biology on a newsstand if they could. (3) There's PLoS, and open-access has lots of promise as a model – maybe they'll start to win out as blog coverage becomes more important as an impact metric?