Many people have redirected their web page, hoping to see a boost in SERP, but nothing happened. Some of them even suffered from ranking degradation afterward.
The fact is, there are good and bad news concerning to 301 redirections. The good news is, when done right, 301 redirects have an incredible power to clean up disorganised architecture, fix outdated content problems and upgrade user experience, while preserving link equity and ranking power at the same time.
The bad news is, when done wrong, 301 redirection can become a fatal disaster. In the past year, since Google has been cracked down hard on low quality links, the potential damage from 301 mistakes increased dramatically. Also, it seems that Google has slightly changed the way they handle non-relevant redirects, which makes proper implementation more important than ever.
The “Perfect” 301 Redirect
To put it in a simple way, a “perfect” 301 redirect is a “change of address” for your content. Normally, this means everything about the page (except the URL) stays the same including content, title tag, images, and layout. When done properly, a 301 redirect passes somewhere around 85% of its original link equity. The new page doesn’t need to be a perfect match for the 301 to pass equity. However, problems arise when webmasters use the 301 to redirect visitors to non-relevant pages. The main point here is, “the further you get from semantically relevant content, the less likely your redirect will pass maximum link equity”.
For example, if you have a page about “labrador,” then redirecting to a page about “dogs” makes sense, but redirecting to a page about “tacos” does not:
This explains why non-relevant pages don’t get a boost from redirecting off-topic pages.
301 Redirecting Everything to the Home Page
SEO experts have known for a long time that redirecting a huge number of pages to a home page isn’t the best strategy, even when using a 301. Instead of passing link equity through the 301, Google may simply drop the old URLs from its index without passing any link equity at all.
While it’s difficult to prove exactly how search engines handle mass home page redirects, it’s fair to say that any time you redirect a large number of pages to a single questionably relevant URL, you shouldn’t expect those redirects to significantly boost your SEO efforts. It’s better, if necessary, redirect relevant pages to closely related URLs. When it comes to page redirections, category pages are better than a general home page. If the page is no longer relevant, receives little traffic, and a better page does not exist, it’s often perfectly okay to serve a 404 or 410 status code.
301 Redirections and Bad Backlinks
Before Penguin, SEOs widely believed that bad links couldn’t hurt you, and redirecting entire domains with bad links wasn’t likely to have much of an effect. Penguin has taught us that “when somebody redirects a domain, its bad backlinks will go with it.”
Webmasters often roll up several older domains into a single website, not realizing that bad backlinks may harbor poison that sickens the entire effort. If you’ve been penalized or suffered from low-quality backlinks, it’s often easier and more effective to simply stop the redirect than to try and clean up individual links. The same concept works at the individual URL level. If you redirect a single URL with bad backlinks attached to it, those bad links will then point to your new URL. In this case, it’s often better to simply drop the page with a 404 or 410, and let those links drop from the index.
Infinite Loops and Its Danger
If you perform an SEO audit on a site, you’ll hopefully discover any potentially harmful redirect loops or crawling errors caused by overly-complex redirect patterns. While it’s generally believed that Google will follow many, many redirects, each step has the potential to diminish link equity, dilute anchor text relevance, and lead to crawling and indexing errors.
New Changes for 302s
Google usually dislikes 302s. However, recent evidence suggests that search engines may now be changing how they handle them, at least a little.
Google knows that webmasters make mistakes, and recent tests showed that 302 redirects have potential to pass link equity. The theory is that 302s (meant to be temporary) are so often implemented incorrectly, that Google treats them as “soft” 301s. Here is a tweet from Duane Forrester from Bing about this topic: