The suffix identifies the name as belonging to a specific top-level domain (TLD). As of late 2016, when this article was written, there are numerous TLDs available for general purchase, including .com, .edu, .game, .green, .hiphop, .net, and .org. The most popular of these by far is .com, which is supposed to indicate commercial sites, but in reality has come to include almost everything.
Registering a domain name lets you create a personal presence on the web. With your own web address, you can control your online identity by linking to any other site with more information about you. For example, you can register a domain name and forward it to a website, blog, or social profile page like your Facebook, LinkedIn, or Twitter pages. A domain name can protect your personal brand and help your career.