Second-level (or lower-level, depending on the established parent hierarchy) domain names are often created based on the name of a company (e.g., bbc.co.uk), product or service (e.g. hotmail.com). Below these levels, the next domain name component has been used to designate a particular host server. Therefore, ftp.example.com might be an FTP server, www.example.com would be a World Wide Web server, and mail.example.com could be an email server, each intended to perform only the implied function. Modern technology allows multiple physical servers with either different (cf. load balancing) or even identical addresses (cf. anycast) to serve a single hostname or domain name, or multiple domain names to be served by a single computer. The latter is very popular in Web hosting service centers, where service providers host the websites of many organizations on just a few servers.
Even when you register and pay for your domain name, you won't necessarily be able to use the name for several hours or even a few days. The domain must propagate, meaning that the official domain name registry must be updated with your website's Domain Name System information. That's something that occurs on the backend without any need of input from you.
While looking at domains, you might come across the name "ICANN" -- the Internet Corporation for Assigned Names and Numbers. This organization accredits some registrars that agree to a set of operational standards, but ICANN accreditation isn't required to sell domains, nor is it necessarily a sign of a company with good customer service. In fact, ICANN plays no role in the sale of many top-level domains, including country-specific domains.
Namecheap — This company provides .com domains for $10.69 (plus 18 cents) per year ($9.69 if you transfer from other registrars). Along with your domain, you get free email forwarding, free web redirection (where anyone going to your domain is automatically directed to another address of your choice), free domain name parking, etc. For the first year (or at least, at the time I checked their prices), you can also have their WhoisGuard (where your particulars are masked from public view) for free. They have a wide variety of domain name extensions available, including .net, .org, .biz, .info, .us, .co.uk, .co, .de, etc. You can use either a credit card or PayPal for your purchases.
When you purchase or transfer a domain to Google Domains, you can immediately start creating your website with one of our website building providers. Plans vary in cost, and options include secure and reliable hosting, customizable templates, and powerful features like drag & drop creation and mobile site-management. To learn more, visit the Help Center.
If you’re still with me then you might be wondering who came up with all of this. The answer is ICANN — the Internet Corporation for Assigned Names and Numbers. ICANN is a non-profit whose role is to coordinate all the names and numbers that keep the Internet online. They outsource a lot of the heavy domain name lifting to registries like Verisign, who pay ICANN for the privilege.
Don’t get discouraged in your domain name search if what you’re looking for is already taken. We have a couple of ways for dealing with such a situation. You can try our Domain Buy Service, where we negotiate acquiring the domain from its current owner. We also offer a Domain Backorder service, where you purchase a backorder credit to give you a chance to get the domain when it goes into auction.