If you are planning to change your website domain, or change the path for file names, you will want to carefully consider the impact to your SEO rankings. The “history” and age of a page are important for SEO.  Web sites and web pages that are well established have more trust, have had time to be fully crawled and indexed, and also collect inbound links that significantly help rankings. If you change the website or page name, then you will likely take a big hit in your SEO rankings, and it will take time to recover (often lots of time!).

So does this mean you have to keep the same domain or path/page names forever? Fortunately, you don’t. There are ways to change your URLs and transfer your SEO history to the new names. The secret here is the effective use of HTTP 301 redirects.

A 301 redirect tells the search engine that a page (or website) has been permanently moved to another location. If you put in place 301 redirects for all of your old URLs to the new equivalent, it will tell search engines the old URL is being retired, and they should treat the new URL as the new name. Thus the search engines will start treating the new URL as the actual page, and work to replace instances of the old URL with the new one in their index. They will also treat links to the old URL as being links to the new one, thus preserving your hard-earned link popularity.

When you change a URL and use 301 redirects, you will typically recover most if not all of the SEO rankings you had previously, though it will still take a little time. Even with 301 redirects, it can take a few weeks for the search engine to discover all the new URLs and work them into the index, replacing the old. This could be longer for sites with low trust (new site or low page rank), or for sites with thousands of pages. If you have improved your URLs, such as a domain name that now contains keywords, or path/file names that don’t have parameters (all that ?name=value stuff), or added keywords to your path/file names, then you will likely improve rankings over the long term.

When you change URLs (domain name, path name or file name), make sure you do the following:

1. Change all instances of the old URLs in your site to the new ones. Don’t rely on the 301 redirects for your internal migration — that will look sloppy to the search engines.
2. Use an HTTP 301 redirect from all old URLs to all new ones.
3. Review your external links and ask prominent sites to use the new URL. Even though the 301 redirects will do most of the work for you, you still want to be collecting those direct links. You can find most of your external links by using the linkdomain:www.mydomain.com command at search.yahoo.com.
4. Always use the same capitalization for a URL for all references (new or old). For example, don’t use www.mydomain.com/ThisPage.html mixed with www.mydomain.com/thispage.html. To a search engine, those are two different pages.

When you do your redirects, make sure to use an HTTP 301 redirect. There are a number “wrong” types of redirects that will prevent your migration from succeeding, and you will lose all your rankings for a long time. Do not use an HTTP 302 redirect, JavaScript redirects, meta redirects or any other such technique.

If you have hundreds of URLs to migrate, you will want to automate the migration somehow. One technique is to use a 404 not-found page handler, which is a page or script that the web server will load when a page is not found. If you can do scripting within your 404 not-found page, you can look up the inbound URL in a table and find the new URL, and then issue a 301 redirect from the page script. This is easy to do with PHP, ASP, JSP and virtually any scripting language. With this approach, you just need a table of old/new URLs that can be read by the script. If you can create an algorithm for mapping old to new URLs (e.g., just replacing parts of the old URL), then the script could be coded to do that as well.

The bottom line here is that with a little work, you can migrate to a new domain or page names, and still preserve most or all of your SEO successes. You will see a dip during the migration, but with the proper techniques it should be temporary.

John Erickson
LeadQual