I recently came across the following post: How To Avoid Google’s Duplicate Content Penalty (For Bloggers)
The main point of this blog post is if you have a single page that can be reached by:
www.blog.com/post
www.blog.com/post/
http://blog.com/post
http://blog.com/post/
Google reads these pages as four separate pages – each with duplicate content. As a result, you get penalized as far as Google ranking goes.
To fix this you should redirect everything to
www.blog.com/post
This way, even though people can enter in four different addresses, it all goes to only one page and more importantly, Google reads it as only one page instead of four pages.
The post goes into great detail about what you need to do. If you are using WordPress you can get the Permalink Redirect WordPress Plugin | SYP. Once installed and activated, this plugin will take care of redirects for you.
Andrea J. Stenberg
