When writing for optimium reach with your useage of specific keywords that are relavant to your site, there is a limit of how many keywords you should use within a post. Keyword stuffing is a well known practice by many sites, but its usage can actually back fire on you.
Stuffing a post, an article or even the content on your site will cause the spiders to look as it as more of a spam post and not add importance to that post. If you do that a lot on your site, you can actually lose ranking overall on Google. The last thing you want is to have your site dropped from Google’s search engine all together.
The best approach for writing for specific SEO keywords is to choose a few of the ones most relevant to your site and use those within your post. For your next post or article, choose a differet set of words. This will keep your content natural to read and interesting too.