How can someone who writes a blog with the title The Scientific Marketer possibly argue against companies doing everything possible to capture the details of the people who view their content. Surely, the first rule of "scientific marketing" has to be to collect data, for without data there is no science. Right?
A lot of companies, particularly those in the direct marketing industry, seem to take it as axiomatic that you should lock up content and make it available only to people who register with you. The (supposed) "benefits" range from the obvious (you get some contact details to use or abuse) to the more subtle (it acts a sort of qualification; only people who are seriously interested will bother to sign up). It might also be regarded as a benefit that you place a small obstacle to your competitors seeing your material, if that's something you wish to prevent.
The clearest disadvantage of the approach is the risk that some genuine prospects will be put off by the process. Indeed, even if they do register, some people will be annoyed at having been made to jump through hoops. Less obviously, there is a different sort of qualification that the company is denied—the self-qualification of people who bother to contact you as opposed to those you call simply because they filled in a form (often against their will) to gain access to some of your content.
But perhaps the most important disadvantage is that your content becomes almost invisible, so you become harder to find. Search engines adore content, and making the full text of papers available on-line makes people who are looking for specific things much more likely to find them even if they don't know your company. Similarly, people are much more willing to link or otherwise refer to content that is publicly available than to content that is accessible only after registration.
So there are significant pros and cons to hiding content, and clearly each case needs to be considered separately on its own merits. Nevertheless, when I started Stochastic Solutions, I took the decision very early that the company would, as a policy, make content available without registration by default. I can't prove that this has been advantageous, but my strong sense is that, over time, people are becoming ever more reluctant to register before there's an obvious reason for being required to do so.
To connect this back to something I do have real and quantifiable experience of, one of the core lessons from looking at incremental response and uplift modelling is that negative effects in marketing are real and much more wide-spread than is commonly believed. I'm always amazed that anyone is surprised by this, given that almost all of us are daily annoyed by various marketing, but most marketers seem to feel that their own messages will be at worst neutral.
Self-delusion notwithstanding, it's hard to believe there's anyone who, when clicking on a link that promises access to some interesting content, doesn't feel some measure of disappointment or irritation when taken instead to a registration form. Should our intrepid surfer submit to the unwelcome interrogation, even the most sanguine is likely to be less than happy if instead of then being taken immediately to the content, she instead gets a message saying that a link will be emailed or (worse) someone will call. People increasingly expect and demand instant gratification, and most are going to feel suckered if even after jumping through hoops there is another level of delay in being granted access to the content they seek, even if it is in the noble cause of filtering out firstname.lastname@example.org, competitors or other undesirables.
So think carefully before locking up content. It may be absolutely the right thing for your business in your situation, but on balance I suspect that most demands for early registration—especially for marketing content—actively undermine the very success that they're trying to generate.