Duplicate content through multiple URLs

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Michael Mason (What No Website): Question Re: rel="canonical"
  
  Now my understanding from what Google provide is that this is really only worthwhile if you serve up duplicate content through multiple URLs.
  
  For example:
  
  • MyDomain.com/page
  • ;www.MyDomain.com/page
  • ;http://MyDomain.com/page
  • ;https://www.MyDomain.com/page
  
  If however I update the .htaccess file with the following:
  
  RewriteEngine on
  RewriteCond %{HTTP_HOST} !^www.MyDomain.com
  RewriteRule (.*) https://www.MyDomain.com/$1 [R=301,L]
  
  Then surely using rel="canonical" on every single page become irrelevant, no...?
  
  Motive: I'm working on a website with an horrendous plugin that's creating incorrect rel="canonical" links and also creating duplicate ones so I would simply prefer to edit the htaccess file and be done with it and then remove these nasty plugins as it seems two are fighting for dominance.
• 
  Edwin Jonk: In theory, yes. However just to make sure the rel canonical can be very helpful. Also keep in mind that many social buttons use the rel canonical too. From memory FB looks at rel canonical before graping the URL from the address bar.
• 
  Edwin Jonk: " I'm working on a website with an horrendous plugin that's creating incorrect rel="canonical" links "
  
  In that case I would not serve the rel canonical and work on the plugin to get the right URL.
• 
  Michael Mason (What No Website): Thanks +Edwin Jonk ;for the quick response.
  
  Typically I will do this:
  • Set the URL through htaccess
  • Update Google Search Console
  • Ensure any plugins do not conflict
  
  However, if you take a look at my site for example: whatnowebsite.co.uk I do not use rel="canonical"  ;as the htaccess file takes care of it and it's not possible to have duplicate naked URLs.
  
  It is possible to have duplicate content of-course as the system generates these files but I manage those individually through the backend.
• 
  Edwin Jonk: Well you do have og:url. I assume those are the right URL's. So why not add rel canonical?
• 
  Michael Mason (What No Website): I tend to use custom code for the home page OG stuff and then allow the plugins to do the other pages (for myself that is) and I also use Google Interactive posts for my Blog area.
  
  This client's site however... Face palm.
• 
  Michael Mason (What No Website): Thanks for all your help on this +Edwin Jonk.
  
  I've resolved the duplicate conflicting canonical references now and I appear to have another issue:
  
  On some pages, I think it's a directory plugin in the WP installation that's causing this, there are 2 canonical references, both identical.
  
  Thoughts...?
• 
  Edwin Jonk: I don't think WP out of the box sets a rel canonical. So are there plugins installed, like Yoast and all in one SEO?
• 
  Michael Mason (What No Website): We actually got rid of All In One in favour of Yoast as it did a better job.
  
  I'm inclined to think it's the directory plugin as the duplicates ONLY appear on the directory pages. Off to look now...
• 
  Edwin Jonk: +Michael Mason ;Only install one or the other.
• 
  Edwin Jonk: Let me ping +Tony McCreath ;
• 
  Tony “Tiggerito” McCreath: On the redirects, test that it forces www to https, as it does not look like it will.
  
  Canonical tags can still have use. For example query parameters may be used that don't change the content. Like utm tracking parameters.
  
  There's no issue in having two canonical tags as long as they say the same thing. But better to get rid of one. However, if there are incorrect ones it's better to not have them as all.
• 
  Michael Mason (What No Website): Thanks for jumping in here +Tony McCreath, appreciated.
  
  Regarding the redirect:
  
  There's a .htaccess rewrite that forces all URLs to https://domain.com so I'm happy that it has been setup OK and it's also referenced as the preferred domain in Google Search Console (WMT).
  
  Regarding the canonicals:
  
  What an absolute bloody headache WordPress is. Now I know why I never bothered with it. No SEO out of box, plugins conflicting with each other and don't get me on to the zero day bugs and hacks that have occured over the last year.
  
  What happened was this:
  
  One plugin (I believe it was All in 1 SEO) was generating a canonical ref back to the home page. A second plugin (I think this was the directory plugin itself) was generating the correct canonical ref a few lines below the first one (but ONLY on the directory pages).
  
  We uninstalled All in 1 SEO and installed Yoast. Immediately the first incorrect canonical ref was gone and now replaced with another identical to the second.
  
  So, given that I never use canonicals as I rewrite with htaccess and where I use a query string it manipulates the delivered content I have no use for canonical references.
  
  I'm inclined to drop the rel canonical entirely but need to find out which plugins are generating the things. I'm pretty sure Yoast is making one but the other has me lost.
• 
  Jim Munro: From the expert panel in this week's SEO Questions hangout on air on 00:26:04 into the YouTube video: https://dumbseoquestions.com/q/duplicate_content_through_multiple_urls +Michael Mason
  
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