One of the lesser talked about features introduced in WordPress 2.7 is the new feature that breaks comments into multiple pages to create faster load times. By default, this feature is activated and set to allow 50 comments before the break. The problem is, with this new feature activated, your WordPress blog is creating duplicate content.
Here is what I found while checking my Google Webmaster Tools account for this website:
Duplicate Title Tags
Is this a huge deal? Probably not, but you may want to consider unchecking this box in your Dashboard > Settings > Discussion tab. Hopefully in a future version of WordPress this will NOT be checked by default and instead be an option.