Duplicate content comes in all sizes, shapes and forms. A very common duplicate content issue with WordPress these days (after the last upgrade) is the comments duplication issue.
Check if your site has this problem with this Google query.
replytocom site:www.yoursite.com
WordPress adds the “?replytocom” link to your comments creating a dedicated, indexable URL for each comment on a single article. The more comments you have the more duplicate… Continue reading