When you have a domain name and a web site, you will still need an ISP to connect to the Internet and to upload your pages to a web server. Your ISP normally wouldn't host your web site. Look at them as the phone connection, and us as the call center. You still need your ISP to get on the Internet and send files to us. But IP addresses are confusing.
Domain names are very, very important to the success of the Internet.
The only way to keep things straight is to use a domain name. Whenever someone gets a new name, it is added to the registry. This registry is available to all ISP's so that they can look up domain names for their customers who are surfing the web. Pretend your phone had no buttons and you didn't know anyone's phone number. You would have to pick up the phone and tell the operator who you want to speak to.