If a post on your blog becomes incredibly popular and starts to rank for a nice keyword, like mine did for WordPress SEO, you could do the following:
create a new page with updated and improved content
change the slug of the old post to post-name-original
publish the new page under the old post’s URL, or redirect the old post’s URL to the new URL
send an e-mail to everyone who linked to your old post that you’ve updated and improved on your old post
wait for the links to come in, again;
rank even higher for your desired term as you’ve now got:
more control over the keyword density
even more links pointing at the article
the ability to keep updating the article as you see fit to improve on it’s content and ranking
