Com, .net, .org, .biz, .edu, .info, .int, .GOV, .mobi, .aero. For many unsuspecting Internet surfers, these dot whatever mean no greater than being an extension name of the websites they are visiting. They do not realize that these three letters coming after a period or dot serve a great function in the webbed world of Internet.
Top-level domain or the last part of an Internet domain name serves as virtual, invisible fences in the immeasurable vast space of Internet. They denote classification and stratification. Top-level domains tell us the kind of website we are about to visit. .com is for commercial websites open for everybody to visit and register on, .biz is for businesses, .edu is for educational institutions (mostly schools, colleges, and universities), and .gov is for governmental agencies and entities. Each top-level domain corresponds to a certain association or classification in an attempt to organize the seemingly-impossible-to-organize portals of the Internet.