Hi, I want to know if my old cms will be replace by a new one deleting all my content, will it affect my Page Rank? thanks!
You will need to use 301 redirects from your existing cms system to the new cms system. When we upgrade a website from one system to the next, we leave the old files in place with 301 permanant redirects to the equivelent new files. All PR will be automatically passed onto your new system when the search bot returns to index the site.
You need to 301 each URL on the old site to the URL on the new site whose content most closely resembles the content found at the old URL. You need to do this on a URL-by-URL basis if the old URLs have backlinks. The reason you 301 redirect the old ULR to the equivalent new URL is to tell the search engines to give the new URL credit for the old URL's backlinks (and therefore, at Google... its Page Rank). The 301 redirect also gives the new URL credit for the link text used by other sites to link to the old URL. This is why it's important to redirect the old URL to a new URL about the same topic... so that link text will be applicable to the new URL and therefore will likely help its rankings the most. If you are hosted on Apache and use Mod Rewrite, once the .htaccess files are in place doing the 301 redirects, the old joomla code can be removed... You only need to leave the old code there if you are doing the 301 redirects inside the code. Mod Rewrite sees all page requests BEFORE your CMS does, so if you've set up your .htaccess files correctly, there is no need to leave the old code there. You will likely notice a hit in your search engine rankings (and therefore traffic) for a month or so after you implement the 301 redirects. Basically you have to wait on the search engines to recrawl every URL that links to your site, discover the 301 redirect, and pass credit for each individual inbound link to the target new URL. How long the process takes depends mainly on how often each of the sites that link to you get crawled. Once all of your inbound links have been crawled and the 301s all discovered, your rankings, PR, and traffic should all return.
How about if I deleted all files and start from scratch.( I don't really need the old files) My domain has a pr of 2. will it be lost once I delete my files? thanks for all your replies!
If you delete all the files, then any pages that would then return a 404 Not Found error would lose all page rank. Your index wouldn't lose the page rank unless you are changing the extension, e.g. going from index.html to index.php, in this case the search engines will get a 404 Not Found error if they tried to go back to index.html. Also any backlinks you have to deleted pages would become worthless. Unless you have some underlying reason to delete them, it would be far more beneficial to just 301 permanent redirect them. I personally prefer to use .htaccess file for the redirects. As Canonical said above, if you use .htaccess, this does mean you can set the redirects AND delete the files without losing page rank, the above statement only applies if you just delete the files without any redirects in place.