Hi
I am looking at a website for a friend and whatever they have used to create it has added
<link rel="canonical" href="http://URL Of Itself.html> to the header of every page.

I thought the use of this function was if you had duplicate content then you use the tag to point at the page with duplicate content that you want to be the master, it doesn't really make sense to just add the tag and point it at itself.

Even though it isn't really doing anything, can the fact that each page has this attribute harm it in Google's eyes?

Thanks,
Dan