The contents of a title tag are displayed in the browser's title bar.
The contents of a p tag are displayed as a paragraph, separated by vertical space from preceding and following page elements.
A div tag is like a p tag except there is no vertical spacing. It is usually used as a grouping element for styling.
A span tag is normally used as a grouping element for styling short segments of text.
Styling for a div or span tag is determined by the stylesheet rules that select for the value of the tag's class attribute.