Identical content is a problem for websites. Sometimes you will have it even if you don’t intend to. Unless the the website is static, there is a chance that a Google bot will find another way to get to a page and will label it as “identical content”.

A useful tool like site search can sometimes be a contender that will turn a page into identical content nightmare. When a link from the homepage or s sidebar links to a page is usually looks like this:

<a href=”page.php”>Anchor Text</a>

When a search results page links to that same page, because of referrer tracking, the link might look like something like this:

<a href=”page.php?ref=search”>Anchor Text</a>

If coming from a categories page the link might contain the category name variable in it, like this:

<a href=”page.php?cat=category-name”>Anchor Text</a>

If the website keeps track of session and needs to pass that via URL that will make another version of the same link:

<a href=”page.php?ses=0123″>Anchor Text</a>

Now Google bot is confused… 4 different versions of the same page… how will it choose which one to label as original and which are duplicate content?

On Thursday, Feb. 12th, Google released a new “rel-ement” that we can use in the link tags. It is rel=canonical. We would need to add this element to the link where we use the URL that we want to be labeled “original”. So our new link will look like this:

<a href=”page.php” rel=”canonical”>Anchor Text</a>

You can read more about this on the Official Google blog.