seo – What are people’s thoughts about rel=”canonical”? Is anyone using it? – Education Career Blog

I just received a memo (dated Feb 29) from our pals at Mountain View. Apparently they want us to start using another tag to specify canonical urls.

As someone who builds a fair amount of websites, this obviously intrigued me, but I was curious to know if anybody else had started using it? Is anybody planning to?


It’s interesting for Wikipedia which intends to have all alternative URLs indexed, e.g. has canonical URL /wiki/Python_(programming_language).

It might also be useful for paged or sorted content, e.g. /foobar?sorby=date with canonical /foobar.

Personally I just prefer to exclude all non-preferred versions of pages from index by adding robots.txt rules (in case of Google it’s simple, because it accepts regular expressions there) and <meta robots>. It saves me bandwidth, and the result is probably the same.


It’s useful if you have a case-insensitive web server, since links into and would be treated as two seperate documents by search engines (thus reducing that document’s page-rank)

Of course, you can get around this with a 301 redirect to the lower-cased version, but using rel=canonical means your users have 1 less HTTP request to make.


I’m already using the Content-Location header correctly. I won’t be in any hurry to implement Google’s new “standard”.


If you have multiple versions of the same content (maybe a print view, or different sort orders) then it seems to be very handy. I’ve used it on a couple pages – haven’t got any data to show its impact yet though.

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