a. Domain Registration
Domain registration is similar to the DMV - it is a lease for your URL (example.com) that assigns you as the legal "registrant" of the domain name.
The worst thing you can do is let someone else register your domain name for you. It's important that it is registered to you, with the billing information in your name, etc... we suggest using GoDaddy for domain registrations, but some other popular services include Network Solutions, Register.com, or Dotster.
If you keep control of your domain, you are free to work with any web designers, programmers, and hosting companies you choose.
TIP: If you change your email address, be sure to update your domain registration's account contact information. If you lose the password to your account, and longer have access to the email address on file (e.g. to reset the password), then you'll need to prove that you are the legal owner of the account by faxing your drivers license, proof that you own the organization, and a recent utility bill. Not a fun process!
b. DNS, Web Hosting & Email Service
Another important component to keeping control of your website is the hosting. This is the physical machine, or server, that powers your site. When you sign up for the domain name (see "a" above), you'll need to tell the registrar how to find your hosting server.
It is important to note that as long as you keep control of your domain registration (see "a" above), you can change to a different hosting company at any time. It is also a common practice to use one server to run the web site, and another server to run email (e.g. Exchange server).
c. Web Site Framework, Content, Updates
Nowadays, pretty much every (quality) site is built with some sort of a database and web-based control panel. Prior to this, they were a collection of linked files and folders. With a database, you can add as much content as you want; each article is entered as a "row" in one of your database's tables. With this arrangement, you can have five articles, or 5,000,000. The admin control panel does the heavy lifting for you!