Since version 1.5, Joomla! has a good SEF urls system, that provides support for all built-in components, and is also used by most 3rd-party extensions. Despite that fact, there are still very many areas where Joomla!'s urls in particular, and Joomla's SEO in general can be improved. That is the primary goal of sh404sef, and has been since its inception at the end of 2006. Working with a web site's urls, sh404sef is also ideally located to add other features that expand Joomla's and 3rd-party extensions. The below list is a small round-up of the most prominent things sh404sef will do for your site:

Ease of use

One of the most difficult part of SEF urls is to actually get started: some SEF extensions requires you to enable a file called .htaccess to operate. A .htaccess file content depends on whatever webserver you are using, or rather how this webserver was set up by your hosting company. While easy in many cases, this can become very hard, and sometimes impossible with some hosting companies. sh404sef (just like Joomla!) can operate without a .htaccess file, and it can make all the difference.

Search engine optimization

• short and keyword-full urls: as it stores urls in a database, sh404sef can handle shorter urls, where all keywords are at the begining of the urls, avoiding things like: www.example.com/component/user/reset for instance
• better handling of multipage articles : each page get it's own sef url:

Joomla: www.example.com/extensions?start=1
sh404sef:  www.example.com/The-CMS/extensions/Components.html
Note that page title, probably the most important on page SEO factor, is also improved in the same way

• ability to taylor urls structure as you see fit. For instance, www.example.com/The-CMS/extensions/Components.html can also be www.example.com/extensions/Components.html or www.example.com/the-cms/extensions/components.html. Pick the one you like most!
• proper handling of duplicate urls: Joomla! has a tendancy to generate several urls for the same page. This comes from its internal behavior (use of "Itemid" to identify pages). This Itemid management has many benefits as it allows to very easily associate modules or templates with a specific page, thus making Joomla! easier to use than many CMS. However, it can have negative effects in terms of SEO, especially if you have many extensions installed. This holds true in 2010 more than ever, based on numerous statements by Google itself . sh404sef will make sure the same content is always accessed with the same url, while allowing you to change that behavior if you want to
• improved page title: often considered the most important element of on-page SEO, sh404sef will improve page title, whenever it can. That means: not always. A manually customize page title is always the best solution, so sh404sef also gives you full control over page title for each page on you site, and the same for meta description, meta keywords, and other tags
• various small changes to a page content, to improve all those small things that can make you go above others in search engine results: use hn tags, tableless output, improved Read more links and many other SEO details that adds up to better ranking

Joomla! implements several security checks in a web server-specific file called .htaccess (these checks are disabled by default, by the way, and enabling them may not be trivial). In cases where no .htaccess file is used, sh404sef implements these additionnal security measures, and add more on top. For instance:

• attack logs (with source of attacks)
• anti-flooding control
• anti-spam protection

All of this is simply enabled at the click of one button.

pageId : your own short urls

 One of sh404sef 2.0 innovation : built-in short urls. Solves common issues with online url shorteners (bit.ly, tinyurl.com):

• users don't know the actual domain name before clicking
• you rely on a third-party for your urls - if they go bankrupt, all your short urls are lost - this already happened in the past, if you wonder

Just use example.com/k3r instead of example.com/a-keyword-full-url.html. Easier to use on Twitter, print on a brochure, tell over the phone...

•  This is the page displayed when a user requests a page that does not exists on your web site. It is a very important one. From a technical standpoint, it should always return a 404 return code, or else search engines will not take missing pages into account and instead will index bad content for your site (Joomla! does not always achieve that unfortunately)
• Equally important is that your visitors are provided with relevant information, so that you have a chance to keep them on your site. sh404sef achieves that in several ways:
• 404 page is displayed as a regular Joomla! page, inside your web site normal page structure (though you have total control about that if you wish to do it differently)
• a user friendly message explains to the visitor what happened. Please note that you have absolute control on this error page content, and can modify it directly from within sh404sef configuration pages
• sh404sef will search for pages on your site similar to the one the visitor requested, in hope this will help her find what she was looking for

Mobile device detection

 As more and more of us are browsing web site using our favorite mobile telephone or pad, it become increasingly useful to provide a better experience to such visitors coming to your site. As a first step, sh404sef will now detect mobile visitors, and switch template on the fly automatically. This means you can design an alternative template for your site, probably simpler, with less modules, a more suitable layout, etc in order to both speed up viewing on telephones, and make page content easier to read for your visitors.

 Make sure the "Offline page" you can enable when doing maintenance on your site returns the proper http code, so that search engines do not index the content of the "Under maintenance" page instead of your actual content!