OneA unique domain name will make your website address more memorable.
A unique domain name is easier to remember and type into a browser. For example, amandasmith.com is more elegant and easier to recall than amandasmith.blogspot.com. It sets you apart so that you are not just another face in the crowd. Plus? Why make your readers and customers have to remember what free content management system you're using so they can find you?
TwoA unique domain name lends your website credibility and/or professionalism.
An individual domain name tells your visitors that you mean it and that you didn't just sign up on whim for a free website account with no real commitment to stick around. I mean, you may have started out that way, but there's no reason to keep looking like that.
Having your own domain says that you intend to stay and that you mean what you say, because it shows that you value your work and the authority of your voice online. People will be more likely to believe in what you put into it and invest a bit of themselves, as well.
ThreeA unique domain name lets you move your website seamlessly to any platform without loss of authority or traffic.
If you ever decide to move your blog to a different content management system, such as from Blogger to Squarespace, but you don't own your own domain name, your url will change from you.blogspot.com to you.squarespace.com, and you will lose a lot of your traction with search engines and readers.
By owning your own domain name, you can maintain your same url if you choose to move your website's home base, and all of the links both within your website and to your website from around the internet will still be connected to your content rather than point at a dead url you no longer use. It gives your website a portability that it otherwise doesn't have.
FourA unique domain name increases your search engine footprint.
If your website url reads you.wordpress.com, a search engine will focus on the main domain name, wordpress.com, because your particular blog is actually only a subdomain of the larger wordpress.com site. A search engine will only see your site as a smaller part of a larger website that isn't yours.
By registering your own domain name, such as you.com, you allow search engines to see your website as an independent site, which lends it more authority. This is important if you want your site to have enough authority to rank your content higher in searches. If you still have something like wordpress.com in your url, you're helping them out more than you are yourself.
FiveA unique domain name gives you greater control over your message and identity online because of your increased search engine footprint.
Helping to establish your website as an authority by making sure it has its own domain name — whether it is tied to your name, your business's, or your weblog's — will allow people to find your site's content faster and more easily than content you might be tied to on search engines that you don't control or don't necessarily want ranked above your own.
That picture of you tripping down the street in a jester's hat that your friend Rob posted? You can make sure your content outranks Rob's photo of you by having your own domain with your name connected to the site.
Also? Owning your own domain name will save you the headache of someone else coming across your site, deciding that they really like its title, and scooping that domain right out from under you. Presto! They might get to outrank you in search engines, and they will likely scoop a lot of traffic out of searches that were actually aimed to find your content. Also, now your message and identity has been muddied by someone else who was quicker on the draw. It would suck to be you.
So, there you have it. It is important to register and use your own domain name for memorability, credibility, content control, search engine juice, and to maintain a clear message and identity online attached to your name or website. If you don't already own your domain name, you should give it some serious thought starting now.
A Good Place to Buy a Domain Name:
I buy all my domain names at MyDomain.com and have for years. I've found that they give me the control I want, and they back up their service with pretty decent customer support. They also don't make me have to look at culturally-sanctioned versions of sexy ladies before I sign up. That's a bonus.
Warning: Be careful to check the "No thanks" links at the bottoms of the pages between picking your domain and paying for it. You don't want to get roped into services you do not want!
Before you buy that domain, please read "5 Best Practices to Consider When You Register a Domain Name". It will save you so much future heartache, you don't even know.