This is a graphic of a very simply and user-friendly website layout. It has a header, that usually contains the website logo and optionally a search box or links to the most important pages, a footer and 2 columns in the center.

The narrow left column is for navigational links (the website menu) and - if space permits - for some advertisements. The right column is for the main webpage content.

Great website layout with 3 columns. Pretty much the same as the above example but with an additional sidebar on the right side.

My personal favorite, as it gives more space to include links to more internal pages as well as advertisements such as banners, Google AdSense and others.