I recently had a situation in which I needed to pass a URL parameter into WordPress so that it could be inserted into all links off of a blog page. For example, a partner would pass traffic to a blog using the format http://www.myblog.com?refcode=joe. All links embedded in the post would need to pass the value of refcode if it existed, even if the visitor requested multiple pages after the initial visit.