Most people realize the need for an Internet presence, particularly for a business. Yet many are satisfied with free services: email provided by gmail or hotmail, a web presence hosted on facebook, reaching potential customers through twitter.
A problem with this is it gives too much control to other persons. Often a free provider of services wants to aggregate data about you and your customers in exchange for the services. Your goodwill, the propensity of your customers to visit you again, is partially in the control of a third party.
You can take control of your Internet presence by registering a domain name.
Actual resources on the Internet are reached by a series of numbers; machines understand only zeros and ones. The domain name system automatically matches up your domain name with the correct numbers for the resource you choose. That means you can direct someone looking for a web page to your facebook page. In the future if you outgrow facebook you can direct your domain name to your web site or wordpress blog. You can direct email for a number of accounts in your domain (such as firstname.lastname@example.org) to your gmail or hotmail account, or you could purchase an email account to avoid sharing your correspondence. You own the domain and that is what your customers use to find and contact you.
If at any time you become dissatisfied with the provider of a service such as email or a web page, you can simply redirect your domain name to a new provider. Your customers do not have to learn a new location. The Internet changes rapidly. Services prominent in the past have disappeared or become unused. If a new, undreamed of service appears on the Internet, you can point your domain or a host in your domain to the new service. (A host in your domain could be something like twitter.mydomain.com which points to your twitter account.) Your customers already know how to reach you in the new service because they have always used your domain name to reach you on the Internet..
Of course a domain name, particularly a .com, makes your business more credible and serious to others. In fact every business providing free services mentioned above owns their own .com.