Since I’m working for the big company now I might just as well point out a few things every once in a while:
So if you have several URLs pointing to the same page or to pages with similar content you can specify one as the preferred one by specifying your canonical.
bq.If your site has identical or vastly similar content that’s accessible through multiple URLs, this format provides you with more control over the URL returned in search results. It also helps to make sure that properties such as link popularity are consolidated to your preferred version.
<link rel="canonical" href="http://www.example.com/product.php?item=swedish-fish" />
The blog post on the webmaster central blog is already over a year old now but I thought it might be worth mentioning: Specify your canonical