If you're being harassed by a certain person or group, or if you've been plagued by a particular person stalking your website and throwing off your analytical data, it's helpful to know that person's IP address. For those who don't know, the IP address is a digital fingerprint of sorts that is assigned to a computer, device or ISP. If you know nothing else about them, know that they're the Internet's way of tracking who goes where, does what, and shows what to whom.
Which is why it's important for you to get the hang of WhoIs. When you get unusual traffic around your website, visit the Whois website and use the "search by IP" function. This will give you specific information about who's looking at you.
Want more out of WhoIs? They also keep track of purchased domain names and tell you who owns what website. Use the URL and keyword checker and get all kinds of information.
I suppose you're wondering why you'd need all this "big brother-esque" technology. The truth is you want to know more about the people who might try to hack or upset your website than they know about you. There's no such thing as too much information.