In reply to Daleus.

The block level and inline level is really the main difference. Maybe an example would help.

Say you wrap a block of text in a div. That text will have a block of space around it. There will be a space between it and whatever elements are above and below it in the design.

If you wrapped a span around that same text that block of space wouldn't be there. Until you style the span the text would fall exactly where it would had you not wrapped it with a span.

An easy way to see the difference is create an html page with a paragraph of text. Take a few words in the text and wrap span tags around them. You shouldn't see any difference.

Then remove the span tags and wrap div tags around those same words. The text should then break out of the paragraph and look as though it's in a new paragraph.