BIG Dilemma about use of rel=canonical

There have always been shady clouds wondering over the use of rel=canonical tags over a webpage. It's just sometime ago that I read an article over searchengineswatch wherein it contained a segment that talks about the use of this tag and about it's harmful effects if used incorrectly. In there the author also recommends the use of 'canonical' tags over duplicate pages and suggests to have a strong strategy for its usage.

Considering it true for the moment, what if one of the sites which isn't under my control, copies my site/pages ? Since I don't have it's control I definitely wouldn't be able to get the tags added to it, BUT it still remains duplicate right.........
But if we add the tag to the pages that I control it'd be more sensible isn't it?

Can someone please help me clear this dilemma? How would you recommend the use of rel=canonical ? should it be over the site that we control or what ? Has anybody experienced a case where the misuse has led to any -ve effects for a website ? How does Google respond if it's been used incorrectly?

Any help in this regards would be greatly appreciated. Thanks.

 

I using rel=canonical on some of my websites (after last google update) and I still testing it, on my website I have pages with 99% same content (file downloads part 1, part 2, part 3 ....) and I have rel=canonical to part 1 page from all other parts!
I using it maybe 7 days but traffic still going down, that don`t helping me...

I know that we need to use it on pages like php pages with same content like page.php?article=222 but also same content on page.php?article=222&comments_order=desc, like you can see if somebody share this second page on some forum, google will index it and you`ll have two pages with same content...

I don`t know how you can use it incorrectly if you know for what you need to use it...

 

You can put the canonical tag at the top of every page you control. If you have duplicate content within your own site, choose which page you want as the official version of the page and set it's canonical tag and the canonical tags of it's duplicate page to that official page. For example, if pages, A, B, and C all have duplicate content, choose the one you want as the official version, let's say it's page A. Then at the top of pages A, B, and C you put <link rel="canonical" href="http://www.example.com/pageA.html" />.

As for other sites that scrape your content, clearly you cannot put the canonical tag on their site. You can, of course, try contacting them and asking them to take the content down (good luck), but if that doesn't work (and it probably won't) just having the canonical tag on your own page will help. It's not a guarantee, but it will help. If the other site doesn't have canonical tag, then you will most likely be seen by the search engines as the real owner of the content. Here's where the canonical tag can be misused. If the other site puts a canonical tag on their pages claiming they are the real owners of the content, then they are misusing the tag and trying to steal your claim to the content. You still can't change that, but at least by having the canonical tag on your site, you have a better chance of winning the battle. It just depends on who Google with trust. If their site has no authority and/or scrapes other sites too, then Google will probably choose your site. Lastly, you can also report them to Google as copyright violators. Google may deindex them.

Hope this helps to clear things up for you.

 

Thanks lesterj for the great explanation. I wast lost with the canonical tag, and your post is very clear.

I'll add it to my webpage.

Thanks.