I had always noticed that majority of person inside the SEO industry are confused about rel=canonical and 301 Redirect. So I had decided to explain rel=”canonical” & 301 Redirect and their importance.
The 301 Redirect – When and How to Use it
301 redirect is designed to help users and search engines to find the piece of content that has moved to a new address. Adding 301 redirect means that the content of the page has moved permanently elsewhere.
What it affects to Users.
Users are not aware that URL redirects to a new location unless the change in the URL in your browser. Even if they make the point that, if the content is still what they were originally looking for, is unlikely to be affected. So in terms of keeping visitors happy, 301 redirects are fine if you are redirecting them to the proper page they are looking for.
What it affects to Search Engine.
Theories says that if a search engine finds a 301 redirect on a URL than it will follow the new targeted URL and stop recognizing the old URL’s. Search Engines also passes the exiting link juice to the new URL, Well it is not sure that they will pass 100% of link juice or the anchor text. Once Google had announced that 301 can pass anchor text, but they don’t guarantee it.
Search Engines also remove the old page from their index so they can provide more and more relevant and quality information to their users. This will take time but no longer than few weeks I had also witness some of my client pages deindexed very fast as expected.
Problems with redirections.
1) Not knowing your 301s from your 302s
The most common problem I have come across is that many developers mistaken their 301 redirects by using 302.The difference between 301 and 302 is that 302 is a redirection which is used the content is temporarily moved to somewhere else and you know that 301 used for permanent redirection. So the link juice and anchor text is unlikely to be passed across from 302 redirect, Results the new page(URL) witness the hard time in term of search engine ranking.
2) Redirecting all pages in one go to a single URL
Another common mistake I see is the migration of the site. An example is if your site has 100 pages that are moved elsewhere. You really should put 301 redirects in these 100 pages that point to the most relevant page on the new site. However, I often see people redirect all the 100 pages to a single URL, usually the home page. Although the intention can not be manipulated, there have been cases of people doing this to try to consolidate all the links from a lot of pages on one page, to make it stronger. This can sometimes force Google to take a closer look of the event and if it happens than believe me your site is in the deep hell of Google spam list.
Matt Cutts talks about this in this Webmaster Tools video:
When you should use a 301
You should not stop using 301 redirects if you are moving your website to a new location or change the URL of a new structure. In this situation, you do not want users or search engines to see the old site, especially if the change is happening because of a new design or structural changes. Google provide clear guidelines here on this and recommend the use of 301s in this situation.
You should only use a 301 if your content have expired on website, as the old terms and conditions, older products or news that are no longer relevant and of no use to its users. There are some things to keep in mind though when removing the old content of your website -
*Check out your analytics and check out, Is the content on the old page are getting any search traffic or not? If yes than, Is it fine with you to loose that traffic?
*Is their any other page which have similar content that you can use to send visitor to? If yes than the take a advantage of using 301 redirect the traffic instead of losing it.
*May the content is useful for future? For example if you have a ecommerce site and have a page with a products which you are not selling or not interested to sell. Is you have any future plans with those products? If yes, than use a redirection instead of deleting that page.
Multiple Versions of the Homepage
This is another common mistake I had seen many times. Potentially a homepage URL can be accessed through the following methods, depending on how it was built -
If the homepage can be accessed via these type of URLs, they should 301 to the correct URL which in this case would be www.blurbpoint.com.
Quick warning – the only exception would be if these multiple versions of the page to a single purpose, as shown to users who are connected or cookies have been reduced. In this case, it would be better to use rel = canonical instead of 301.
The Rel=Canonical Tag
Rel= Canonical Tag is relatively new tool for SEOs to use and was first officially announced in February 2009. Amazing it has been a part of SEO from pretty long time but still one of the most misunderstood feature of SEO.
As I mentioned above it is one of the most misunderstood concept of SEO. And many of my clients had some really bad experience while putting tag on all their pages pointing to their homepage and unfortunately Google aggressively notice the canonical tag and flush all the pages out of its ranking. The most interesting and surprising part is that Google says many times that they are having a hard time to trace rel=canonical tags but peoples stories say that Google punished their sites very hardly as they used this tag in a wrong manner. However experience has shown that they take notice of it most of the time – sometimes despite pages not being duplicates which was the whole point of the tag!
When to use Rel=Canonical
Where 301s may not be possible
Unfortunately there are situations where the implementation of 301 redirects can be very difficult, perhaps the site’s developers do not know how to use it (I’ve seen), maybe they just do not like you if you ask them to do this. Technically, a rel = canonical tag is a little easier to implement, since they do need to do anything server side. it’s just a case of editing the <head> tag of the page.
Multiple Ways of Navigating to a Page
This is a common problem in large e-commerce web sites. Some of the categories and subcategories may be combined in the URL, for example,
Both of these pages might return the same result set and therefore is a duplicate page. A 301 is not appropriate that you would like to save the URL in the same format as what someone has visited. Therefore, a rel = canonical work well in this situation.
Again, if this situation can be avoided in the first place, then that is the ideal solution instead of using the canonical tag.
When dynamic URLs are generated on the fly
By this I mean that URLs are usually database driven and can vary depending on how the user navigates through the site. The classic example is the session ID each time they are different for each user, so it is not practical to add a 301 to each of these. Another example might be if you add tracking code to the end of the URL path to measure certain URL or clicks on certain links, such as:
When Not to Use Rel=Canonical
On New Websites
I’ve seen some cases where rel = canonical is used in new websites – this is not what the label has been designed. If you are in the fortunate position to help with the structure of a new website have the opportunity to make sure you avoid situations where you could get duplicate content. Make sure you do not happen from the beginning. Therefore, there should be no need for the tag rel = canonical.
Across your entire site to one page
Just a quick comment on this case since this is a way for the rel = canonical tag can hurt you. As I did this as an experiment and killed most of my site. I put the rel = canonical tag through my entire site pointing back to the home page of the website and Google reindexed a large part of my website as a result. The following snapshot from Google Analytics pretty much sums up the effect:
In short, you should be careful when using the 301s or canonical label. Such changes have the potential to go wrong if they do well and can hurt your website. If you are not 100% sure, do some tests on a small set of URLs first and see what happens. If everything seems fine, implement changes gradually in the rest of the site.
As for choosing the best method, it is best to consider what you want for the users and you want to see yet. Then think about search engines and content you want the index and the authority and pass link juice.
Reference: SEO guide by Blurbpoint.