advantages and disadvantages of using new html5 semantic elements

The inclusion of a main element (or similar) has long been debated in the working groups with authors and others often questioning why we had new elements such as

,
, and
but no element to accurately describe the primary content of a page. The semantic roles of some existing elements have been improved to make the code more insinuative. please share them with us in the comment section below! They are two dimensional representations of knowledge.Mathematically a semantic net can be defined as a labelled directed graph.. Semantic nets consist of nodes, links (edges) and link labels. HTML5 also has new elements like
,
,
and