When you’re changing the structure of your website, changing your primary domain or creating better URLs for SEO purposes, you want to keep the values of your old URLs and move them to the new URLs. Luckily there’s an easy solution for that: 301 redirects. 301 redirects let your server tell the visitor (or search engine) that the page they are trying to visit has been moved permanently to another location. Visitors will be sent to the new location directly. Search engines will try to remove the old URL out of their index and move the value of that page to the new location. For some time now Google is telling us that 301 redirects are the proper way of redirecting your pages. However 301 redirects seem not so good for SEO after all.
301 redirects and PageRank
An import measure of the value of a page for Google is the PageRank. When you’re moving your pages you would want all of the PageRank from the original pages to be relocated to the new locations you specify in your 301 redirects. But in an interview in January with Eric Enge, Matt Cutts confirmed that with using a 301 redirect there might be some loss of PageRank. Too bad Matt didn’t really explain why. In my opinion moving a page, shouldn’t make that page of any less value. It’s still the same page with the same information people originally linked to. Imagine changing your company name or optimizing you URLs for SEO purposes. You would be forced to change all the URLs of your website and you would lose a little bit of PageRank for every redirect. But that means losing a little bit of PageRank for every page on your website and decreasing the authority of your whole site.
301 redirects and relevancy
Besides authority in the form of PageRank links also pass relevance to the page they’re pointing to. One way links pass keyword relevance is through the anchor texts of the links. With a redirect there could be some problems however, since the link doesn’t point directly to the new page but through a redirect. Google says in a video that anchor texts typically do flow through 301 redirects. However they don’t promise this will always happen based on the trust they have in specific redirects. They’re giving a signal here there are situations where anchor texts won’t flow through a redirect.
In a test Dave Naylor for example proved that in a specific case an anchor text wasn´t passed through a 301 redirect. Over a year ago Patrick Altoft noticed the same behavior for some 301 redirects. Google could do this to prevent Google bombing or maybe to decrease te value of redirecting links for link building purposes. The consequences of not passing anchor text relevancy through 301 redirects however can be enormous. When changing your domain you could lose all relevancy you carefully built with the use of anchor texts. So search engines should be really careful with this.
In a practical case Mark Lavoritano proved that moving domains had no significant impact on the search traffic Google generated. However the search traffic from Yahoo! And Bing decreased dramatically. So while Google is telling us 301 redirects could not pass all the value and could cause a decrease in findability they seem to handle it the right way. They´re probably just trying to tell us not to buy links and redirect them to our websites to increase our findability.
What to do when changing your URLs?
When you need to change you URLs there is no real alternative for using a 301 redirect. So 301s are still the best way to redirect but consider the fact that you could lose authority and relevancy along the way. Where Google seems to support the function of 301 redirects very well, other search engines aren’t that good. This forces you to consider the need of changing your URLs and makes you think about creating URLs that you don’t have to change any time soon. W3 advises to create good URLs by leaving out:
- Authors name– authorship can change with new versions. People quit organizations and hand things on.
- Subject. This is tricky. It always looks good at the time but changes surprisingly fast. I discuss this more below.
- Status– directories like “old” and “draft” and so on, not to mention “latest” and “cool” appear all over file systems. Documents change status – or there would be no point in producing drafts. The latest version of a document needs a persistent identifier whatever its status is. Keep the status out of the name.
- Access. At W3C we divide the site into “Team access”, “Member access” and “Public access”. It sounds good, but of course documents start off as team ideas, are discussed with members, and then go public. A shame indeed if every time some document is opened to wider discussion all the old links to it fail! We are switching to a simple date code now.
- File name extension. This is a very common one. “cgi”, even “.html” is something which will change. You may not be using HTML for that page in 20 years time, but you might want today’s links to it to still be valid. The canonical way of making links to the W3C site doesn’t use the extension.
- Software mechanisms. Look for “cgi”, “exec” and other give-away “look what software we are using” bits in URIs. Anyone want to commit to using perl cgi scripts all their lives? Nope? Cut out the .pl. Read the server manual on how to do it.
- Disk name – gimme a break! But I’ve seen it.
You can use creation dates however, because they won’t change afterwards.