I have to disagree with the suggestion to NOT ask for registration> I think that you'll get much more response if you feature a white paper that people want to read so badly that they'll register up front. Then anything that they do with the call-to-action at the end (which you should be all means include) is gravy.
It's a good debate. And even better test. It's something marketers should test and run with what gets the best result - most likely measured by lead quality, volume, and sales.
I wish I had the link for you now, but I read an article at one point by a guy who made those websites that get you to opt-in to a horoscope subscrption to your phone.
His finidings through testing were that when he requested a zip code up front, his initial click-through rates were lower, but his response rates on the back end were much higher. It turned out that people who gave a little information up front were much more likely to give a lot more later on. It really boils down to trust.
