Yes, many firms do this.
I prefer to NOT gate data sheets and make those web pages instead. My personal preference is that much of this content is open and available as a web page, video, etc and not as a pdf. That's how I like to evaluate vendors instead of having them force me to contact them before I'm ready. Of course, since I'm trying to get people to give me their info, I have to gate some of the content. Try to find truly valuable items and gate those; or cut up documents and post those for free, but make people register for the full edition.
There is an ongoing debate about this. If you want things to go viral, keep it open! See webinknow.com for some other thoughts on how this works.