What's wrong with the GET method
The GET method of transferring parameters between Web pages is by far the simplest method. It is particularly useful for passing parameters from within HREF tags. For example, assume you have a set of articles on your Web site and a single script that displays the articles in the desired fashion.
If you wanted to provide a simple hyperlink using <A HREF> to a particular article, you would need to pass the script a parameter telling it which article you would like to view using the GET convention. Unfortunately, Web spiders generally ignore hyperlinks that include parameters in the URL. This means that the page which the hyperlink points to -- as well as all pages referenced by it -- will be ignored by the Web spider indexing your site.