Google penalizes web sites that practices keyword stuffing, stringing together keywords to increase the keyword density and hopefully show up more in the search engines.
As an example, the German website of the luxury car BMW was banned and removed from the Google index in February 2006 because of keyword stuffing. With Javascript enabled (IE default), you see a nice clean minimalist layout with the BMW car upfront and center. When you disable Javascript, however, hidden texts show up wherein keywords are strung together. A classic case of keyword stuffing.
Google found out and yanked them out of their search engine. It cause quite a stir then because this is BMW afterall, not a mom-and-pop website.
Here are some news and blog entries on Google banning of BMW.de
Google blacklists BMW.de http://news.com.com/2100-1024-6035412.html?tag=tb
BMW given Google 'death penalty' http://news.bbc.co.uk/1/hi/technology/4685750.stm
German BMW Banned From Google http://blog.outer-court.com/archive/2006-02-04-n60.html
On a mom-and-pop scale, this website is nowhere to be found on Google (not even as a supplemental result) possibly due to keyword stuffing. They string together phrases using their keywords in an attempt to rise high up in the rankings, only for the strategy to backfire. Try to do a site:www.johnmall.com command and you will not find anything in Google
http://johnmall.com/
If you are thinking of doing the same thing, refrain from it. It's not going to do you any good