Why do I need a domain name?

i. Domain names are your Internet address. Most domains are registered by businesses as a way of providing information to and communicating with their customers. Many businesses register their domains in multiple countries in order to protect their brand internationally. Owning your own domain and purchasing hosting also allows you to have a personalized email address and website. Rather than using generic emails like hotmail and gmail you can have: e.g. joe@joesbuilding.com.
ii. Domain names are portable. With your own domain name, you are no longer tied to your Internet Service Provider (ISP) to access email or host your website. This means you won't have to change your email addresses if you change ISPs!
iii. Domain names improve search engine rankings. Search engines rank websites with their own domain names higher than those using an ISP address.
iv. Domain names show professionalism. It is better to have www.yourdomain.com rather than something like:
http://www.yourisp.com/user123/
Using your own unique online identity for your web site and email will build consumer confidence, as this is a clear demonstration that you are serious in the way that you conduct your business on the Internet.
v. Domain names are memorable. A long website or email address at your ISP can be difficult to remember. A short, relevant domain name is memorable and will increase traffic to your site.