Initially, I had a great idea for a business name and website: let's just call it something.com.
Anyway, I did a whois search (i can't remember where but I usually use whois.net, which prominently displays the "HOVER" icon on their page). If memory serves me, this time I did a GoDaddy whois search instead. GoDaddy listed the domain as available and I registered it, and set it to private. I paid $60+. It turns out that I got so busy I never checked for my emailed receipt and after further research, my credit card didn't go through because I hadn't updated my billing address. My attempt at registration was on or around 11/30/2015. I just did a whois and my site has been taken by someone else with quite a few domains registered already. From the WHOIS information, it looks like the site was registered by that "someone else" on the same day!
I tried to request that he sell me the domain, but Hover wants $199 just to talk to him!
It could be that all whois.net traffic is monitored by Hover.com and somebody uses that data to quickly grab sites that people search for. I have no idea. Just a wild theory.