Websites on Facebook (tabs)
There are 3 basic types of Facebook pages: personal, group, and fan/commercial.
The personal pages are obviously designed for individuals. Individual pages have a privacy component and individual can restrict who sees their posts.
The group pages are moderated pages where everyone in the group can post and share according to the group topic. While people with privacy labels on their personal pages are unable to share their posts with the group, the group page has a posting option allowing post made on the group page to be now shared publically.
The commercial/fan page has a distinction in that it is “liked” not “friended”. Personal pages have a number limit on “friends”, commercial pages have no limits on “likes”.
In addition, commercial pages can have custom tabs. In opening the tab there are various possibilities, but the most common is simply opening a webpage that appears in the Facebook “frame”. If the page is made to large, scroll bars automatically appear. The webpage that appears can do just about anything a webpage normally does including links to non-facebook sites.