By default, WordPress automatically converts URLs within the comments into clickable links. Although, it is a very helpful feature, you might want to remove it. As it attracts spammers who post their stupid links through these comments.
Quick Tip : Restricting WordPress Search to Titles Only
To disable links from comments in WordPress, copy the following code and paste it inside your functions.php file.
remove_filter('comment_text', 'make_clickable', 9);