When I receive an offer or inquiry, I tend to do a little research before replying. I want to see who is interested in acquiring my domain name, and I also want to see why they might be interested in buying the domain name.
To do this cursory research, Google, LinkedIn, and even Facebook are the primary tools I use. Typically, I can find out all I need to know within a few minutes of searching.
One of the best tools that can be used though, is one I use every day: Whois searches. Despite GDPR being in effect rendering this tool less useful, it can still be helpful.
A Whois search is helpful because it shows who owns domain names in other extensions. Owners of alternative extensions (.net/.org, ccTLD, or new gTLD) sometimes want to get the .com domain name. Not only might a Whois search show this information, but it would allow me to see what the other website is doing. This can help with pricing, and it can also help ensure that parking is not infringing on the other business’ IP (a whole other ball of wax).
It’s a good idea to check the Whois records when trying to do some recognizance about a prospective domain name buyer. Be sure to check the most common extensions, but don’t neglect the ccTLD extensions and new gTLD extensions. Since there are many ccTLD and new gTLD extensions, the IP address, phone number, or even email address domain name could be helpful in narrowing down where to look.
Bonus: One other tool to use is a Google “inurl” search.