The four basic web site structures are:
Sequence

A simple linear way to organize material. Sequential structure usually works
best with smaller web sites.
Grid

A grid structure is a complicated web structure which is best suited for information
where the audience has some basic knowledge of the topic.
Hierarchy

A hierarchical structure is an excellent method for organizing complex information
around a single home page.
Web

A web structure provides a free flow of information, but may be difficult
for inexperienced users to follow.