Somehow, you will need certain information of a (or some) certain website for certain reason let say so. And, you must know to find such information toward certain website; you may deal with two ways. The first one is through DNS lookup. DNS or domain name server is like a phone book on your cell phone or your note book where they are filled with certain number or certain domain. Simply say, DNS is really well to describe the name of a domain into a series IP address number. For those who are not familiar with DNS, then this is how it works.
When you place or write or put certain domain name in your search engine, a DNS translate it into IP address to let your Internet Provider to bring you to certain website you want. Then, is it possible to find out certain IP address of certain website? Of course it is possible. More, there are some services that you may find on net free or paid that give you access to discover some website IP address just by writing down its name. Domain records lookup is one of them and the lookup result will be something like TXT, NS and many more.
The second one when you want to know more about particular information of a particular website is through whois lookup. Whois is a system which is filled with any particular information toward a domain name or a site such as its ownership or the kind of information whether that domain name is already registered or not. Addition whois also fills with the expiration date of a website or domain name. Hence, if you have particular interest toward such site you can simply find what you need by using the service that is provided to you by the previous site that mentioned above.