How to avoid duplicity with Canonical link?

Question

I have a question about the use of Link Canonical.

Canonical link is a tag element <link> which aims to decrease the amount of Urls with duplicate content.

Sometimes we see some Urls with the same content and so, the relevance of that page disperses among the others, splits the pagerank, causing the main URL to lose relevance, as in the example below, different urls point to the same page.

Ex: http://www.meusite.com.br/index.html or http://meusite.com.br

The Canonical link is set in this way:

Head of the site index:

<link rel="canonical" href="http://www.meusite.com.br" />

Head of the contact page:

<link rel="canonical" href="http://www.meusite.com.br/contato" />

Now, my question is the following, 301 redirects, via file .htaccess are another way to do this, or complement this technique?

Answer 1

A controversial subject that creates a lot of confusion and debate, understanding a little how the two work:

Redirect 301

It tells search engines that the page is no longer at that address and has permanently moved to a new page. Tells engines to remove that page from its index and index the new page. This has always been the default for permanent page forwarding, it tells users that the original page is no longer relevant and that the content is on the new page.

Common problems: If you do not have access to the server side is not an option. Another disadvantage is that search engines may take a little longer to reach the new page. Misuse can also cause problems, when for example redirecting all pages from an old site to the main page of a new site, this undermines the relevance of all search traffic and can result in a high bounce rate.

When to use 301

• By default - this is the preferred method of redirecting
• Pages that are being permanently moved or replaced
• Domains that are permanently moved
• 404 pages and expired content (assuming the relevant content or a page exists)

Canonical

Informs search engines that there are versions of the page, more to keep the content only of the favorite version. Informs that the other versions will be available so that people can visit, but to keep only the index of the preferred page. Although incorrectly used as an alternative to 301 is a completely different approach. Unlike the 301 that physically sends the user to the new page, the Canonical only serves to inform the search engines. When you have pages with similar or very similar content is when you should use Canonical, example:

You have two pages to list your store’s products, one list of products in alphabetical order and the other for price, and the two have different Urls, so if you keep it that way, search engines can index both. If your preferred page is the one that orders by price, you place the Canonical in the alphabetical order page and inform that the price is the most important.

Common problems: It is only a suggestion, although the engines take into consideration, they are not required to follow. The most common misuse of the tag is when it is implemented on pages that do not include a large percentage of the same canonical page content. Unless they contain considerable chunk of duplicate content, it probably shouldn’t be used. Another common misuse occurs with multiple related pages. For example, you have written a blog post that has been split into several pages with your own Urls, informing only the first page of the post even if the others contain relevant content, will make the search engines never go the rest.

When to use Canonical

• When 301 cannot be implemented, or take too long
• Duplicate content, but if you want to keep all pages active
• Dynamic pages with multiple single-page Urls
• Considerations between domains where both sites are similar, but must remain active

SOURCE in English