Do commerce sites with product filters need to canonicalize filtered URLs to prevent duplicate content problems?

Question

I'm thinking about using rel=canonical for search filter URLs. If I use this tag, my web pages with parameters never get ranked. If I do not use this tag, it may cause duplicate content problems.

www.example.com/cctv/companies

This page is about CCTV companies. .this page optimized for general keywords like "CCTV" or "Buy CCTV".

I also want to filter the content with properties like "Network Type" or "Brand Name". Then the URL, Title and Meta description change and content is more closely related to visitors interest:

www.example.com/cctv/companies?brand=samsung&country=china

This page is optimized for long tail and more closing keywords like: "samsung cctv types" or "chines cctv models".

If I use rel=canonical for second (filtered) URL, the second URL won't rank. Some long tail keywords will be lost.

If I do not use canonical tag, problem is duplicate content. Some content on the filtered URL would duplicate the first (main) URL.

Answer 1

Having some duplicate content within your site is not a problem. If a page has too much duplicate content, Google may choose not to index it. If there is some duplicate content, Google may choose not to include the duplicated sections of the page in the index for that page. Google won't penalize your entire site for duplicating content between pages. See What is duplicate content and how can I avoid being penalized for it on my site?

Your strategy of changing the titles and meta descriptions of your pages is a good one. Google is much less likely to drop a page from the index when the title and meta description are unique.

With product filters you also need to be careful not to allow Googlebot to crawl too much. If you have ten filters with four options each that can be applied on a page there are 10^4 or 1,048,576 possible different pages that Googlebot could crawl. As a general rule never let Googlebot crawl a page with more than one filter (or possibly two for popular combinations) applied at the same time.

Answer 2

If the page changes due to filters are significant enough, it is a new page. There is no reason to think otherwise. It is not necessary to use a canonical tag if the filters change the page enough not to get into trouble. You need to check this of course. I used to use this method for several pages on my site that could potentially create 250,000 or so pages. I opted to remove them due to low value, but I was using it primarily for navigation. In your case, you are using the same method for content. It should work as long as the filters change the page enough to be unique and do not create low value content or pages with too little content.

Answer 3

Categorize everything and make a hiearchy (tree) to represent each product.

You already have your domain. Here I'm gonna call it example.com. The next text that should follow is any major category where many of your products fall under.

So if you ran a store, and it only sold a wide variety of items but a third are premium items and a third are standard items and a third are discounted items, then the first text could be one of those three things I mentioned and you can begin your tree like this:

http://example.com
http://example.com/premium
http://example.com/discounted
http://example.com/standard

Do keep in mind that each URL needs to have unique content. For example, http://example.com can talk about a few best sellers and why they sell well.

This URL:

http://example.com/premium

could present information about what it means when products are premium and then example products can be displayed.

Then you can keep going deeper. So if you sell premium forks, premium plates, discounted cars, discounted apples, standard paper, and a standard computer, then you can have URL's like this:

http://example.com
http://example.com/premium
http://example.com/discounted
http://example.com/standard
http://example.com/premium/forks
http://example.com/premium/plates
http://example.com/discounted/cars
http://example.com/discounted/apples
http://example.com/standard/paper
http://example.com/standard/computer

Then for each additional URL I added, you talk about each item and why its in that category. For example, You can talk about forks and why they are premium.

As a bonus, you can define a naming convention so that navigation keywords don't follow it. Take a look here:

http://example.com
http://example.com/premium
http://example.com/premium/Page:1
http://example.com/premium/Page:2
http://example.com/discounted
http://example.com/discounted/Page:1
http://example.com/standard
http://example.com/standard/Page:1
http://example.com/standard/Page:2
http://example.com/standard/Page:3

As you can see, I added a colon in the name and defined a rule where an item category name or item name cannot contain a colon because if it does, then navigation could be messed up. As for the above URL's you could redirect

http://example.com/standard

to

http://example.com/standard/Page:1

unless you're writing unique content for each page (meaning where the first URL is a nice intro and the pages list the content)

Nevertheless, make sure the content between each page is unique enough and use unique titles and unique meta descriptions and try to have 300 words per page.

Once you get into a habit of categorizing then you should never run into a duplicate issue again.

Answer 4

Ok, then I'll add to my answer. Categorize more.

So you could have standard red tv's and premium blue monitors and premium blue tv's.

Have URL's like this:

http://example.com/standard 
http://example.com/standard/red
http://example.com/standard/red/tvs
http://example.com/premium
http://example.com/premium/blue
http://example.com/premium/blue/monitors

Then in the first URL, list some things that are standard then explain why they're standard. Then for the next URL, list some things that are standard and red. Do the same with the 4th and 5th urls but think premium. The 3rd and 6th url are product pages.

I think in your URL, network may be a feature that applies to certain items, so anything like that can be mentioned on the actual product page itself.