Why do the Search Engines Care?
They don’t really care; they’re machines. That being said, there’s a lot that can be implied and inferred from it being a machine. Structure and organization appeals to a machine because it makes it easier to read.
Examining the BODY Tag
Just as there are vital tags for the <HEAD>, so there are some for the <BODY> tag. From the perspective of the search engines, some tags will highlight parts of the page that are more important than other parts.
Dissecting the HEAD Tag
There are a few elements inside the <HEAD> tag that you need for your site. If you overcompensate, you could be penalized by the search engines instead of getting rewarded. What I’ve listed below are the only tags the search engines use; they ignore everything else.