Forbin001 - 1:41 pm on Jul 13, 2011 (gmt 0)
On page is many factors, the heading, keywords in title, size of fonts, keyword density, etc.
There are about 200 signals that google checks for rankings. Think of it in 4 groups, Positive on page, positive off page, negative on page, negative off page. All are constantly monitored to see if youre up to good, or no good.