Layers
Div tags are a great addition to HTML and has helped form the internet into more than just boxes and tables. Using divs has never been easier than with CSS.
Although if divs are done incorrectly, they may cause problems with some versions internet explorer. Since most browsers are based on W3C and IE is not, it causes many problems with margins, padding, height, width along with other CSS.
Layers are done by created div tags along with the use of CSS. Here is the example: <div>Content here</div>.
Divs as layers
The use of CSS is needed greatfully for div tags to be worth while. Using css positioning along with other class and id is a great way to start.
Divs as divisions
In addition, divs may be used as divisions instead of layers. In this case, they may be used to highlight text, add color, along with many other features.
As an alterantive to tables
All in all, divs make a great alternative to traditional HTML and tables. They add to the creativity of a site and is always a great addition.