Just found a very informative two-part article by Tim Archambault, New Media Coordinator at Bangor Daily News/Bangornews.com. He explains why they decided to require reader registration at their site, and how it affected things.
He notes, "An approximate 12 percent drop in page views occurred during the first month, but the number of pages quickly recovered
to its previous level during the second month. There was no extraordinary marketing efforts to increase our page views."
Also, although the newspaper's registration count of 90,000 is bigger than its print circ count of 63,000 circ for the print daily, just 10% of online registered users are subscribers to the print version. To get this fairly high registration rate, they did a promo with a sweeps for $50 worth of lobsters.
Archambault also noted that requiring registration means your customer service will rise dramatically. 66% of customer service
queries in the month of March were due to online reg queries, mostly people having trouble with passwords.