Canonicalisation Tag

I actually ran some testing on this a couple years back and url's with trailing slashes tended to be prominent, but with the canonical rel tag it ended, which is what you should be using anyhow. Even worse is when I see a site with multiple/duplicate pages with variable extensions like .com, .com/index, .com/index.htm, etc. because not only does this confuse Google but they may also pick the wrong page as your primary because of internal and external links pointing to it. I see this happening mostly with internal links though, but either way if you have 100 links with half going to one and half to the other you are splitting the benefits they offer. On your index page go into WMC and name your primary domain selection.

1. Choose one URL as the preferred version. If your site has a directory structure, it’s more conventional to use a trailing slash with your directory URLs (e.g.,example.com/directory/ rather than example.com/directory), but you’re free to choose whichever you like.
2. Be consistent with the preferred version. Use it in your internal links. If you have aSitemap, include the preferred version (and don’t include the duplicate URL).
3. Use a 301 redirect from the duplicate to the preferred version. If that’s not possible, rel=”canonical” is a strong option. rel=”canonical” works similarly to a 301 for Google’s indexing purposes, and other major search engines as well.
4. Test your 301 configuration through Fetch as Googlebot in Webmaster Tools. Make sure your URLs:
   http://example.com/foo/
   http://example.com/foo
   are behaving as expected. The preferred version should return 200. The duplicate URL should 301 to the preferred URL.
5. Check for Crawl errors in Webmaster Tools, and, if possible, your webserver logs as a sanity check that the 301s are implemented.
6. Profit! (just kidding) But you can bask in the sunshine of your efficient server configuration, warmed by the knowledge that your site is better optimized.