Dealing With Duplicate Content Issues on WordPress Comments Pages

I saw a tweet today about WordPress comment page duplication issues related to SEO. While the word is still out as to just how much damage it does or doesn’t do to your ability to get found by the Great G, this specific problem is relatively easily fixed — and not by disabling the paged comments feature that the Wizards of WordPress have so kindly coded for us (you ever had a post with 300 comments? you’ll understand what I mean…).

All it takes is a little bit of code in the functions.php file in your theme. If you’re uncomfortable editing your theme files or don’t know how, leave a comment and I’ll whip up a little plugin. This may be a good time to learn to edit your files, though

This little bit of code doesn’t affect anything but WordPress comment pages. If you use WordPress for something other than a plain-vanilla blog, you may need the horsepower of Yoast’s Canonical URLs plugin for WordPress.

So in your functions.php file, insert the following code (I split the echo lines up for clarity, normally they’d be all on one line):

function canonical_for_comments() {
 global $cpage, $post;
 if ( $cpage > 1 ) :
  echo "\n";
  echo "<link rel='canonical' href='";
  echo get_permalink( $post->ID );
  echo "' />\n";
 endif;
}
add_action( 'wp_head', 'canonical_for_comments' );

Make sure you paste the code before the last ?> characters at the end of the file.

For those of you who care, here’s a quick explanation of what the above code does — you’ll get a short intro into the behind-the-scenes functioning of WordPress.

When a visitor navigates beyond the first page of comments, the variable $cpage contains the page # that’s being displayed. The $post variable contains all of the information about the post. The function tests to see if we’re on a comments page greater than 1, if so, it spits out the <link rel=…./> characters. But where does it spit them?

That’s controlled by the add_action line. We’re telling WordPress that when it’s building the head section (‘wp-head’), to add our special ‘canonical_for_comments’ function.

Simple, easy schmeezy.

Tagged as: add_action, canonical, comments, cpage, duplicate content, functions.php, get_permalink, google, plugins, wordpress code