duplicate content question

lets say u have 30 threads tagged with tag "vbseo"
u also have another tag "vbulletin seo" which has 40 threads including all 30 that are tagged with vbseo as well.

then u go create a sub forum named Vbseo which all of these 40 threads and maybe a few others.

is this advised or not. can this be identified as duplicate content with negative results ?

or it can have positive results since there is more keyword density in the forumdisplay pages of the vbseo sub forum ?

Links aren't content. Tag pages are effectively search results pages. I recommend placing little emphasis on trying to index tags. Index the REAL content.

so if the site/vbseo.html (forumdisplay) has the almost the same links as /site/tags/vbseo.html there is nothing wrong with that

It's certinaly not ideal, but I wouldn't say it's bad. Even forumdisplay is BARELY a content page. It too is just a collection of links more or less.

When ever possible, focus on the threads themselves, as that is what really matters.

ok 1 other how about adding forum description above the threads that belong into a certain forum. good or bad, even if adding via default vb options or by relevant replacement h2 etc

You can use the RR's for that , and is the recommneded use of them.