Originally Posted by JohnScott
10 to 15 occurences, or 10 to 15 different keywords?
And no, they do not impact rankings very much, not in SERPs full of anchor text driven rankings.
I recently experimented with keyword density and onsite SEO and guess what? Got #2 spot in Google from #12 within next 2 days. The keyword I was optimizing for is going for $2-3 per click in AdWords. Thus, keyword factor on the page is still in place.