I may be a bit late off the blocks, but I just learned about a rather nifty little feature buried within Go Daddy that lets you see when somebody has done a Whois lookup on one of your domains.
Log in to your Domain Manager, click Tools, click Exportable Lists, click Add New Export, then check the relevant boxes in the wizard.
The feature exports a .csv file telling you how many Whois searches have been run against each of your domain names in the last day, week, month and year.
I imagine this could provide a few useful data points when deciding how much interest there is in a domain you’re planning to sell.
I also found it quite interesting that more people executed Whois queries on domainincite.com in March than bothered to click the About tab at the top of the page.
Domain people are an odd bunch.