SEO Canonical Tags & Duplicate Content
To get you started
Never Contain Duplicate Webpages in your Web Server ( Or Webpages which are slighly different )
Say accidentally you made a copy of a wepbage and forgot to delete it from your server. This will surely damage your SEO depending on the duplicated webpages
Duplicate webpages confuse the crawlers. The crawlers might not even index the original Webpage if there are duplicates of it on the server
Sometimes the crawlers, will index one of the duplicate webpages and exclude all other duplicate webpages. This is sometimes bad as this gives the freedom for the robots to choose the original webpage for you
So always have one copy of a webpage on your server!
Secret Duplicates
You might not reallise but, your homepage or other webpages may have duplicate webpages even though you have one copy of the webpage on your server file manager
Let's see an example
www.revisezone.com/ www.revisezone.com/home.html revisezone.com/
All these 3 tags lead to the same webpage. So for crawlers they are seperate and duplicate content
How do you choose the one to be indexed?
All 3 will work but, google crawlers only allow one url to be indexed on google
This is how we choose it
<meta rel="canonical" href="https://revisezone.com/">
This tells the Crawlers that this is the original url to be indexed!
You can do this for other webpages if you want but, google does this automatically
Only do this for the important webpages
You can do this also if you have duplicate webpages but, we recommend you to delete them!
It's better to delete them but, if you made similar webpages to run on different devices. For example, you have a webpage to run on desktops and a seperate duplicate webpage to work on mobiles then you need to use canonical tags for every webpage
<meta rel="canonical" href="https://revisezone.com/">
Usually, we canonicalize the desktop version and redirect the user if it is a mobile version - https://m.revisezone.com/