There is a message to that effect when non-subscribers read a sublinked article like this. Sometimes with a trial offer. The occasional (occasional!) posting of subscriber links is, I think, one of the best marketing tools we have.
Jon, I've been looking into a lot of elements of information goods, and there are a few bits I'm coming to realise, slowly (it's only been 30 years I've been studying this).
1. Information is a public good. Nonrivalrous, only very difficultly excludable. Strong positive externalities. Hal Varian's got a good piece on this. Doesn't mean you cannot sell it, but it means that doing exclusively has serious negative effects.
2. Free-sample giveaways are almost always an excellent idea. John Dvorak's recent "Whatever Happened to Wordstar" had an excellent illustration of this:
Worse, in 1985, the company produced Wordstar2000, a copy protected program that was nothing like the older lovable Wordstar and which contained annoying copy-protection features that scared most users away. While many pundits including Esther Dyson predicted great things for Wordstar2000, users rejected it. The product was big and slow and expensive. And despite complaints by the company and others, people wanted software they could copy and use on more than one machine. During this era piracy sold software and created market share. People would use a bootleg copy of Wordstar and eventually buy a copy. Wordstar may have been the most pirated software in the world, which in many ways accounted for its success. (Software companies don’t like to admit to this as a possibility.) Books for Wordstar sold like hot cakes and the authors knew they were selling documentation for pirated copies of Wordstar. The company itself should have just sold the documentation alone to increase sales.
3. Corporate and foundation grants and sponsorships or support may be an option. I've been following the Rockefeller Foundation's "100 and Change" program with some interest -- the application process is structured to also seek projects benefiting from other forms of support.
