Next are third-level domains, which are written immediately to the left of a second-level domain. There can be fourth- and fifth-level domains, and so on, with virtually no limitation. An example of an operational domain name with four levels of domain labels is sos.state.oh.us. Each label is separated by a full stop (dot). 'sos' is said to be a sub-domain of 'state.oh.us', and 'state' a sub-domain of 'oh.us', etc. In general, subdomains are domains subordinate to their parent domain. An example of very deep levels of subdomain ordering are the IPv6 reverse resolution DNS zones, e.g., 220.127.116.11.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.ip6.arpa, which is the reverse DNS resolution domain name for the IP address of a loopback interface, or the localhost name.
Dotster.com — This registrar provides fairly cheap domain prices ($15.75 plus 20 cents per domain), a convenient web interface to manage your domains, an optional privacy facility where your domain name is registered in the name of a proxy company, etc. They offer .com, .net, .org, .biz, .info, .us, .ca, .tv, .name, .cc, .de, .sr, .md, .co.uk, .us.com domains, etc. If you're transferring a domain here from other registrars, the price is even cheaper ($6.99 plus 20 cents). Both credit card and PayPal payments are accepted here.
A great domain name is a concise, easy to type, and memorable URL that reflects your brand or your website’s subject matter. Avoid using hyphens, strings of numbers, or unnecessary words to make it easy for your visitors to remember and find your website. Remember: A great domain name is one that your visitors can type correctly on their first try.