How do these internet sites get created and maintained for discussion forums, such as this one?

Is there a program out there that someone can purchase? How do you set up a webiste and register as the owner of that site? Is there some kind of national registry for websites?

Are topic / discussion forums in reality "web-driven data base" programs? How does one govern such a forum, given the huge amount of people that participate? Are there a set of standard rules that most forums adhere to?

What steps does one need to take to begin such an endeavor? How do you ensure that Google would put your site in the higher rankings?

Thanks in advance for any help rec'd...

There are several BBS systems that can be run from a website. This site uses one of the more popular ones. A search for WEB BBS or FORUMS should find some examples. And yes, they are database systems.

The first step would be to purchase a domain, then contract with a WEB host service to host the site. Next would be familiarizing yourself with the software and setting up your site. Finally you need to try and drive traffic to your site.

You would need a web hosting account and judging by your post, it appears as though you want your own domain (::: YOURNAME.COM ::: (http://www.yourname.com)) to go along with. You will want a web hosting account that supports a scripting language such as PHP or ASP. I can refer you to some hosting providers that include different forum apps with their packages.
--Jason