Redirects for SEO: Soup to Nuts

As any good SEO knows, redirects are a must when you are changing URLs or moving your site to a new location. But why are redirects so important? And what are the best practices for creating redirects? Without further delay, here is the comprehensive guide to redirects for SEO.

Why Redirects?

Redirects of the “301” HTTP status code variety send the message that a resource on the Web has permanently moved. Google (via Matt Cutts) says that when they encounter a 301 redirect, and the content at the new URL is similar to the content at the old URL, they will allocate the old URL ranking signals to the new URL. This is good news for SEOs, as it means they can change URLs without having to start from scratch in terms of links and other ranking signals.

Setting Up Redirects

For small sites doing a redirect plan is straightforward. Just redirect all the old URLs to the best-fit URLs on the new site. Best-fit meaning the content on the two URLs is as similar as possible. In Appache this typically means editing the Htaccess file. On Microsoft IIS it is slightly more complicated. In IIS remember to set the status code to 301 or you may end up with a sub-par for-SEO 302 (resource temporarily moved). If you are using a modern CMS, you can usually set up redirects via their interface as opposed to via the server software.

Creating Redirect Plans for Large Sites

An awesome redirect plan for large sites will include old-to-new URL mappings for several categories of URLs:

  • URLs to redirect based on content
  • URLs to redirect based on inbound links or other signals
  • URLs to redirect based on existing rankings

However, executing on a plan for sites with thousands or millions of URLs presents a unique set of problems. For example, it may not be wise to add thousands of rows to your htaccess file, as making the file too large could potentially cause problems. I limit my htaccess to 1,000 rows to be on the safe side. If you want to add more, be sure to test to see how well it works.

An alternative for dealing with large numbers of redirects to htaccess is to leave the URLs in place and add meta refresh redirects pointing to the new page. This takes the load off and preserves the search equity of the URLs.

It’s also a huge task to manually create thousands of old to new URL mappings. Some approaches to managing the scale problem for enterprise sites include the use of mapping rules, only redirecting URLs with identical content on the new or migrated site, and prioritizing redirects based on various factors.

Creating Rule-Based Redirects

If your URLs are changing in a consistent way, you can create a rule that processes them all dynamically. For example, if your press release folders are changing from /press to /newsroom you can create a single rule that automatically processes the mapping.

Prioritizing Based on Content

Most large site redesigns involve consolidation or elimination of content to some degree. This means that old URLs may not have an exact match in terms of content on the new site. Since it appears that redirects that point to completely different content often lose most of their value, it may not make sense to redirect pages that are in reality going away. Google recommends letting URLs that are removed generate 404s (which says somewhat cryptically that the resource was not found), or 410 (which makes it clear the resource is gone).

Prioritizing Redirects Based on Search Equity

Another approach is to pick a few thousand URLs that are especially important and redirect those. But how to choose? One approach is run an inbound link report on your site and redirect any URL with external inbound links. This should be a key consideration for any redirect plan, and many SEOs will stop here. But I advocate for an additional analysis – redirects based on existing rankings. Some SEOs include elements like tweets, G+s, and even user signals like page views, and other factors into the analysis.

Redirects Based on Existing Rankings

It seems that SEOs are in 100 percent universal agreement that ranking reports are bad, bad, bad, so I risk censure by suggesting you use them. My experience shows, however, that an old URL ranking for a competitive keyword should 100 percent be redirected to the best-fit URL on the new site. Even if the URL has no ranking signals to be seen in any of your reports. Why? Because the ranking is almost certain to drop post changeover if you do not explicitly redirect it to the new version of the URL. I have seen it happen again and again, and trust me, clients (and bosses) notice.

Use Visibility Reports to Benchmark Rankings

The key to preserving high-profile rankings in a redesign is to pull an organic visibility report. There are tools that monitor millions of keywords and spit out a report showing all the rankings they have for a given domain. This allows you to know what URLs are ranking even if you do not have a huge strategic keyword list. Just export the list of ranking URLs and map them to the new URLs on your site.

Strategic Mapping of URLs to Content

Another technique to consider is to strategically map multiple URLs, preferably with ranking signals, to a single high-value URL on the new site. This (in theory) has the effect of concentrating search equity from the old site onto a single destination URL.

This technique should only be used when there is an obvious match in terms of content between the old URL, the links pointing to the old URL, and the new URL. If you can’t make this semantic match, then don’t waste the redirects by attempting to consolidate them on a bad URL, point them to the best possible match on the new site.

I have tried the consolidation tactic several times and it seems to work, i.e. the new URL draws more organic traffic than the old URLs, but it is very hard to say definitively that this is due to the redirect strategy and not other changes.

Allowing Requests to 404

Just because you can put in a redirect doesn’t mean you should in every case. While this is a controversial topic, evidence suggests that a redirect pointing to an unrelated page has limited value. For example, a retailer I worked with recently redirected thousands of old product pages URLs (which previously generated 404s) to their home page and saw zero effect on Google. In other words, thousands of product URLs, many with ranking signals, had no effect when redirected to the homepage of the site. The message seems to be if the URL redirects to a page with drastically different content it will pass little to any SEO value. I suspect that the amount of time the URL was 404’ing may be a factor as well.

Conclusion: Redirects Are a Pain

For all but the smallest sites, creating redirects is a hassle. Yes, it’s boring work, and it may be tempting to blow it off, but it’s the kind of work that pays off big time down the road. Instead of feeling blue, find satisfaction when you launch your new site, fully expecting organic traffic to drop, and instead see it remain steady or even (gasp) go up! Then you will know the power of the redirect, my son. And what’s more, you will be man.

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