This field on the comments form of your blog is one of the ways spammers use to share their content.
One quick way to cut down on your website being used as a spam spot is to remove this field. To do this there are 3 easy ways and they are outlined beautifully in this blog post on Crunchify.com.
IF you are using the code into the functions.php file you do not need to have “crunchify_” in the code. You can simply removed this portion out of both places and the code still works.