How damaging is duplicate content in a forum?

[TheEnigmaticT]

Hey all; I hunted around for this in previous questions in the Q&A and didn't see anything. I'm just coming back to SEO after a few years out of the field and am preparing recommendations for our web dev team. We use a custom-coded software for our forums, and it creates a giant swathe of duplicate content, as each post has its own link. For example:

domain.com/forum/post_topic

domain.com/forum/post_topic/post1

domain.com/forum/post_topic/post2

...and so on. However, since every page of the forum defaults to showing 20 posts, that means that every single forum thread that's 20 posts long has 21 different pages with identical content.  Now, our forum is all user-generated content and is not generally a source of much inbound traffic--with occasional exceptions--but I was curious if having a mess of duplicate content in our forums could damage our ability to rate well in a different directory of the site.

I've heard that Panda is really cracking down on duplicate content, and last time I was current on SEO trends, rel="canonical" was the hot new thing that everyone was talking about, so I've got a lot of catching up to do. Any guidance from the community would be much appreciated.

[AdamThompson]

Yes, having duplicate content in your forum could hurt your ability to rank.

And yes, the canonical tag sounds like the best way to deal with your situation.