Most of the problems I see with SEO are matters of degree: lost opportunities, underutilized content, technical issues on some sections of the site. But occasionally I see full-fledged SEO disasters and these usually occur in conjunction with a site redesign. Here’s why.
Almost all site redesigns involve adding, deleting or changing content. That usually means changing URLs, and sometimes the domain name itself. If another site links to your page at http://www.mysite.com/my-popular-page and you change the URL to http://www.mysite.com/myservice/my-popular-page the visitor following the link will get a File Not Found error. What is worse from an SEO standpoint is that Google will drop the original page from its index since the URL is no longer valid, and you will lose “credit” for the link pointing to your site.
During a site redesign many, if not most, of your URLs will change, and that means that you could lose the value of thousands of inbound links developed over all the years your website has been online. Since Google weights inbound links heavily in its ranking algorithm, the URL changes could cause your rankings and your search engine traffic to plummet. What makes this a true disaster is that the damage can be permanent.
Preserving Google Rankings with 301 Redirects
Thankfully, there is a simple way to avoid an SEO disaster when you redesign your website. Google recommends using 301 redirects to send visitors to old URLs to the relevant new ones. The redirects should be set up so that each old URL is mapped to the most relevant new URL.
These redirects are typically added to a text file (called .htaccess) that resides on your server. Depending on the types of changes to your site, you may be able to use a rule based on regular expressions to redirect pages of your site, but often you just have to do the tedious work of mapping each URL.
For example the line redirecting the above-mentioned URLs would look like this in your .htaccess file:
redirect 301 /my-popular-page http://www.mysite.com/myservice/my-popular-page
If the 301redirects are in place when the new site is launched, your link popularity will be preserved, your visitors will have a much better experience, and you will retain more visitors, since they will not land on File Not Found pages when following links to your site. All this makes for a much more successful site redesign!
Avoiding disaster is important, but there can also be tremendous SEO benefits from a site redesign done well. If you or someone you know is contemplating a site redesign, do consult with an SEO expert at the start of your planning process so that your shiny new site brings lots of shiny new customers too.