You can earn 20% on all sales generated through your affiliate links.
When visitor try to reach page that doesn't exist on your site, he/she will see the "page not found" error page. This page is known as 404 page. What visitor will see, depends of browser he/she is using. The page is not user-friendly, and what's more important for you, the visitor will probably leave your site after experiencing such error. Here's how such error page looks in Firefox 3 with Google Toolbar installed.
Joomla installed on your server will change default browser's 404 page to something what you can see on this picture. It's not perfect, but still better than default browser error page. At least, there's a link that leads to the home page of your web site. Not bad, but could be much better.
Look at the statistics of your web site if you can. You would be surprised how much hits had 404 error response code, even if all links on your web site are correct. So, where they come from:
First, in Joomla administration panel create a content page where visitors will be redirected after 404 error. Some nice examples of such pages can be found here. Use Google to find even more examples. Assign a menu item to the page, and place it in a hidden menu (a menu which module is not published). Now, you have a link for this page that looks as a regular Joomla article link. It can be with SEO enabled or without it.
The "system" template is included in the Joomla 1.5 installation. The file error.php located in <JOOMLA_ROOT>/templates/system handles display of error pages. In the beginning of this file, you should make a redirection to the custom 404 page you created. So, open it in editor and after line
add code:
Redirection will be made only if type of error is 404, so you should finish if-then statement by adding
at the end of this file.
On Joomla 1.6 the code should look more like this:
Since we are editing a template that comes with Joomla, it's possible that it will be changed in some of the next revisions of Joomla core. Remember to re-apply this hack after upgrade, if needed.