I think that a large number of people buying domains can't get their first choice name because some "parked domain monetization" operation
(cyber-squatter) owns it and is making money running ads on the page. The trick is to sign up for millions of domain names; set up pages and run ads on them; after 1 day delete domains that have no traffic; after 3 days delete names that have some traffic; after 5 days delete pages with marginal traffic; keep the 1% of pages that have enough traffic to be worth keeping the domain. Because of the refund policy, the 99% of pages deleted before the 5 day grace period are refunded in full and the "monetizer" gets to keep the ad revenue generated over those 5 days. (This is called "domain tasting".) See the DNForum page for more information on how this business works. Interestingly, I think Google AdSense probably has boosted the viability of this business. I wonder what percentage of Google's posted $2bn (or so) / yr "traffic acquisition costs" goes to this business. According to Ram Mohan from Afilias, 3 of the big 5 registrars say that they make over $5m-$8m / year from parked domain monetization pages. This means that these people are making more than that from these pages and Google and other ad servers even more.
I wonder if there is any way to close this loophole that effectively enables a no-risk business. I think these monetization businesses are a net-negative value to the community and seems like a loophole exploit. On the other hand, refunds are a legitimate service for legitimate registrants. It is VERY difficult to tell the difference between a legitimate and illegitimate registrant.
In the jungle of such pages, the Kevin Kelly page stands out as my favorite example of responsible domain name use.
UPDATE: WSJ November 17, 2005: "Revenue from text ads on these sites will total $400 million to $600 million world-wide this year and may reach $1 billion by 2007, according to Susquehanna Financial Group analysts Marianne Wolk and Roxane Previty, who track the online ad industry."
UPDATE: Google has an AdSense page targeting domain name parking businesses. I wonder if these Google folks will talk to us? They should know the size and shape of the "professional registrant" community better than anyone else and it appears they are "taking to them" directly from the looks of this page.