A good friend of mine just shared a blog post from SEOmoz with me a few mornings ago. I don’t keep up too much with SEOmoz these days, so it’s good to have someone point out when they write something that is more relevant to what I do – no offense SEOmoz, you’re cool!

Last week there was a pretty interesting blog post at SEOmoz, written by Everett Sizemore, worth checking out if you are about to embark in a website redesign, relaunch, or any kind of work that will result in a change of URL structure on your site.

Sizemore’s post inspired me to breakdown what he wrote about, and add some of my own experience to the mix. While SEOmoz’s audience are mainly composed of more savvy individuals such as myself, my blog targets business owners and people who really need to just understand what the heck we’re talking about. So this is for you Mr. Business Man!

To dumb it down, if you’re changing your site in a way that your URLs will change, –THIS IS IMPORTANT- you should read this whole post. Here’s an example of what I’m talking about:

• Your contact page is going from http://www.example.com/contact.html to http://www.example.com/contact-us/
• This applies to when the URL structure is changing, as exemplified above, as well as when the actual domain name is changing (going from www.exampledomain.com to www.newdomain.com for example).

If this is happening to your site, chances are most or all of your URLs are changing too.  Let’s start with the basics:

301 Redirects – What, Why & How?

Redirects are commands that we give to the search engines (and other entities) when we need to, well, redirect them elsewhere. Search engines are robots, and although they are really smart, their algorithms don’t always “get” the semantics of a website. Take this scenario as an example:

You are a lawyer, and you have a really old website for your law firm. It has some outdated content, some stuff doesn’t work right, and let’s be honest, it’s ugly. So you hire a nice chap like myself, or another cool dude or dudette to help you out. We work together and design a beautiful, simple, user friendly, and up to date website that truly represents your law firm. In this process, we restructure the content, create search engine friendly URLs, etc. When we are ready to “turn off” the old site, and “turn on” the new one, we have one crucial step to take in order to not lose any of the current keyword rankings and authority your old site has gained over the years (it doesn’t matter if you ever put effort on your old site or not), and that is setting up 301 redirects.

There are different types of redirects, and we’re not going to cover all of them here because all you need to know in order to accomplish the task of successfully transferring rankings and authority from your old site to your new site revolves around 301 redirects (a.k.a. permanent redirects).

The redirect commands are written in a file named. htaccess, and that file lives in the root folder of your site. That is if you’re in a Linux server. If your site is hosted on a .Net (Windows/ASP) server, then kindly close your browser now and get the hell out of my face. (just kidding, but really, that sucks for you)

There are many tools available for free to help you build 301 redirects into a. htaccess file. Having said that, if you are reading this post you probably don’t know a whole lot about this stuff, so I wouldn’t recommend you messing with this because it’s a pretty easy way to bring your whole site down and mess things up. If I were you, I’d get in touch with me for help, but if you want to try your luck, here’s where you can go to learn how to build this.

301 Redirects – The Problems

Let’s say you got in touch with me, and we were able to help you get the redirects setup prior to launching your new site. Or maybe you did it all by yourself? Now what?

Now we have to do a few tests to make sure everything checks out, and that the redirects are working as they should. Once all is confirmed, we push the site live (since this post is about the redirects, I’m ignoring all of the other stuff you need to do prior to launching your new site).

Okay, your site launched, everything seems to be working (knock – knock – knock on wood). We check the redirects by trying to access some old URLs and notice how we’re being redirected to the new locations. For example:

• Our old contact page was at http://www.example.com/contact.html. So we type that into our browser and we are immediately redirected to the new contact page, at http://www.example.com/contact-us/.

We even ping the old URL to see the server response and ensure we have a 301 redirect being picked up.

Phew! Good work everyone, we did everything right so the search engines will have no issues and everything will work splendidly right? NOPE! Well, maybe yes, maybe not. We just don’t know how the search engines will react, so we watch, we monitor, we act paranoid for a couple of weeks and we make sure everything is checking out.

If all steps were taken correctly, chances are that over the course of a few weeks, the search engines will “learn” the new site with the assistance of all of our redirects and on page optimization, and all of our rankings will stabilize. Expect your rankings to fluctuate after the launch, regardless of how well you think the redirects are setup.

Houston, we got a problem!

Let’s say that a week goes by, two weeks go by, and you are just watching more and more of your rankings disappearing, and things don’t seem to be going well at all. The first thing you do is double and triple check all of the work, is anything missing? Fix anything that may not have been done correctly. If everything seems like it was done correctly, don’t go crazy. You could have done the most perfect job with your redirects and still run into problems.

This takes us back to what the SEOmoz post was about.

Remember, everything we are doing is geared towards making the process of re-learning the site easier to the robots that are run by the search engine’s algorithms. Sometimes, those robots do things that are unpredictable, or have faults that cause problems for us, or even work “too well”.

The case study presented by Mr. Sizemore shows a site relaunch project where everything was done to the T, and yet, they saw a tremendous loss after the site launch. So what happened?

Although this is rare, it could happen to your site. In this instance, Google indexed the new URLs of the new site right away, but continued to have the old URLs in their index. The problem is that due to a lack of an entry point into the old URLs (even the sitemap.xml had been updated with the new URLs), they had not be re-cached since the launch of the new site. While Google indexed the new pages with ease, it didn’t know what to do with the old URLs in its index, and the 301 redirects worked, but it was almost completely bypassed by the search engines.

Mr. Sizemore, being the smart dude that he is, turned the old linking structure back on to allow an entry points to the old URLs. This let the crawlers get back to the old URLs, and be redirected to the new ones. Shortly afterwards, the problem was reversed.

This is an example of a rare event that can happen when you’re messing with 301 redirects. One of many things that can go wrong.

I hope you enjoyed this post, and please feel free to let me know if you want to see anything added through the comments below.