Many people are transferring their websites to concrete5 from other platforms, or from static html websites. In most cases the page addresses on the old website and the new one will differ.

Example #1:

• Old site URL format: /products.html
• concrete5 URL format: /products/

Example #2 (let's assume that is a "Books" section in online store):

• Old site URL format: /products.php?category=12
• concrete5 URL format: /catalog/books/

Example #3 (let's assume you have multiple files and you want to keep control over them via cms, but the download links are already spread over the web)

• Old site URL format: /download.php?file_id=12345
• concrete5 URL format: /download_file/82/

The problems solved by setting up 301 redirect (so-called "Permanent redirect"):

• search engines will know the new location of the old-style URLs, the page ranking should not be lost ( http://www.google.com/support/webmasters/bin/answer.py?answer=83105 );
• if there are any external links to your old-style URLs, they will continue working and visitors will get to a proper page instead of annoying "Page not found"

Please note that by default concrete5 allows to set 'Additional path' for a page via page properties, but this will work only for pages like an example #1 and not for an example #2 or example #3. So, if your website consisted of just few .html pages, you don't need this addon, don't waste your money.