What does the CANONICAL tag mean?

HI to all ,

I want to know what is canonical tag? and what are the purpose of these tags…if anyone know then please let me know…

A canonical link is a url declared at the top of the page to alert search engines which version of the page to index. For example, a page might appear as page.html and also page.html?sid=asdf314159265. You can prevent search engines from indexing these two links separately by making the canonical link page.html. (If both are indexed, they might share PageRank.)

These are handy explanations:

Don’t waste your time Ralph, there’s a fine line between answering questions from spammers/ encouraging new members / encouraging new members who apparantly don’t know how to use Google or have two brain cells to rub together.

OK I am still confused and would be grateful for an explanation to clarify these Google Webmaster Tools “Fetch as Googlebot” results.

As you can see the “redirect 301” from the old URL seems to be working and also the new “canonical link” but the page content is not being displayed?

If I submit the new canonical link to Googlebot the web page is displayed OK.

HTTP/1.1 301 Moved Permanently

Date: Mon, 22 Nov 2010 14:24:29 GMT

Server: Apache/1.3.42 (Unix) mod_gzip/ mod_log_bytes/1.2  mod_bwlimited/1.4   mod_auth_passthrough/1.8 FrontPage/ mod_ssl/2.8.31 OpenSSL/0.9.7a

Cache-Control: no-store, no-cache, must-revalidate, post-check=0, pre-check=0

Expires: Thu, 19 Nov 1981 08:52:00 GMT

Pragma: no-cache

X-Powered-By: PHP/5.3.2

Set-Cookie: PHPSESSID=40e45ffbab4af169f582ead6258c2381; path=/

Location: http://WEBSITE.COM/New-SEO-Page-I-would-like-to-be.html

Connection: close

Transfer-Encoding: chunked

Content-Type: text/html

It is the search engine friendly URL. In other words, a canonical URL is the URL that you want visitors to see (i.e) Home page.
For ex: Following URL’s are the same


The fact is that these are all different URLs. This become an issue to search . Hence the idea of canonicalization solves it.
To know more refer Canonical URL .

Canonical url is the main url that makes the search engines and user to visit in your site. With same content your site can have multiple url. Canonical tag for the search engines is been provided to decide the duplicate content within your website…