Canonical Tag - Question

[AdiRste]

Hey,

I will give a thumbs up and best answer to whoever answers my question correctly.

The Canonical Tag is supposed to solve Duplication which is fine.

My questions are:

1. Does the Canonical Tag make the PR / Link Juice flow differently? If I have john.long.com/home and john.long.com but put a Canonical Tag on john.long.com/home reading john.long.com then what does this do? Does it flow the Link Equity back to john.long.com?

2. Can you use the Canonical Tag to change PR flow in any means? If I had john.long.com/washing-machines and john.long.com/kids-toys...

If I put a Canonical Tag on john.long.com/kids-toys reading john.long.com/washing-machines then would the PR from /kids-toys flow to /washing-machines or would Google just ignore this? (The pages are completely different in this example and content is completely different).

Thank you.

[AlanMosley]

Yannick is correct.

Bing for example will lose trust in your site and start to ignore your tags if you are not honest.

Bing has also stated that a canonical is much like a 301, only it leaves the useer on the page, it does not redirect. So yes it will leak a bit of link juice.

Read the link yannick supplied, it explains it all.

[THB]

"Would Google just ignore these"

The canonical tag is merely a reference for Google, and any other crawlers that respect this tag, and in no way does Google have to honour it.  I'm quite certain if your canonical tag reference was different than the actual URL in question over a large chunk of your site, Google might start to think something is up.

The canonical tag works like a 301 header redirect.  So, it will pass some juice, but not 100% of the PR juice.

I could go on more, but there are several answers below that have already pointed out some great points.

[de4e]

To answer this questions needed to understand why google have implement "canonical" tag.

Before, to determine is content  duplicated or not. Google bot downloaded page content and via complex algorithm compare it with other page in index. As i think there are special bot  running through indexed pages database and searching duplicates (that's why copy-paste sites take ban not right after indexation but in some time after).

Tag "Canonical" make this task more easier, Google bot  don't need to download page with duplicate content, just need to check section, and may be hash or something like "hashsumm" for . So there are no necessity to download and store same data few times(delete stored data is hard for high-load data centers).   It's more effective and fast way to crawl large data sets like web. Also link and url related data, i think, should be added to primary page data set.

I've made a test on this, Google download much less data if the page has rel="canonical" to other page, compare to primary page.

So according this answers for your questions are:

1. Link just flow as usual's, all link data for duplicated pages merge with data for primary page. So PR may slightly decrease in some cases,by the way if you have links from same pages to both  primary and duplicated pages. But impact is not critical, almost similar to 301.

2. No, because Google bot check not only canonical. About this i have one more point, Google is statistical SE, and rate pages on topics, so in you case  even if canonical will added to pages, it will not help you rank better for both terms.

[Alex-Harford]

1. I think a canonical loses a similar amount of link juice as a 301 redirect would, so 100% of the juice would not flow back to john.long.com

2. If Google sees the canonical link is different to the content of the page it is on, Google will ignore it - Matt Cutts has said as much.

Check this out: http://www.mattcutts.com/blog/rel-canonical-html-head/

[YannickVeys]

Read this:

http://www.bing.com/community/site_blogs/b/webmaster/archive/2011/10/06/managing-redirects-301s-302s-and-canonicals.aspx

[AdiRste]

Thanks for your reply Yannick. It's much appreciated.

I don't find you very convincing though.

I'll give you a thumbs up but I need somebody else to answer please.

[YannickVeys]

In my opinion, if you are pointing to a page as a canonical and the page you are pointing to is not a copy of the page the tag is on, you'll be sending strange signals to SE's and they will ignore it. Worst case they will penalize you. (But I dont think they do that)

[AdiRste]

But my question is and what I'm trying to understand is that - IF it does flow Link Equity like you said it does, then what is to stop somebody putting Canonical Tags into Internal Pages pointing back to their Homepage to channel Link Equity from Internal Pages back to their Homepage for example????? Would Google just ignore these or penalise you because will Google know that the content isn't the same?

[YannickVeys]

1. In my understanding: it flows link equity back to john.long.com if it is a copy of /home.

2. It's not as simple as that. Try not to compare a canonical to a 301. rel canonical tells SE's that there is a copy of the page somewhere else. So putting a rel canonical on the kids toys to the washing machines will do nothing for your rankings. They are not copies of eachother.