How deep should I let my forum be spidered

[StevenMapes]

I run quote a niche website that's been running since late 1999 and over that time I've built up something like 4000 resources which consist of either text articles or image galleries and reviews along side another few thousand news stories relating to the niche interest.  On top of the main site I also have a forum which isn't especially optimised for SEO and I was wondering, whilst was cleaning it up, whether anyone has any tips / suggestion / best practices for forum SEO.

Because it is all UGC the quality of the posts can be quite weak so I was wondering whether I should block robots completely from the forum, which seems a little harsh, whether I should let the whole forum be spidered (which seems a little excessive and potentially a bad thing) or whether I should restrict things to that only the main index and perhaps one page of topics and their posts be accessible to robots and then nofollow the rest?

Any thoughts?

[LukeyJamo]

Hey mate.

UGC can actually be very high quality content, and subsequently I would let Google run wild through all the content.

Forums can be tricky and you would want to make sure Google doesnt index any duplicate content.

I would use this tool, http://home.snafu.de/tilman/xenulink.html to crawl the forum. Export to Excel and then assess all the URL structures and see if it's picking up any strange parameters or duplicate content.

I would block the weird paramters in Google webmaster tools, and if technically possible 301 all the duplicate content issues. The problem with restricting things in robots.txt is that you might actually block link juice accidentally.

Hope that helps - my background is more in ecommerce but im sure we'll have similar site structure issues.