best domain for VBseo??? Expert help needed

I just bought Vbulletin and wll be upgrading to vbseo. I have yet to install it yet, and am wondering if it matters which domain I use?

For instance

keywordforum.mydomain.com
mydomain.com/forum/keyword

Which one will be best, or is this an non-issue??

I want to make sure that the SE's asociate all forum content with my primary domain. So, would the sub-domain be a detriment to my primary domains rankings? In otherwords, will the SE take all content from subdomain forum, and put it toward my primary domains rank strength? Or use it ONLY towards the sub domain.

If that makes sense

Mike

I like this
keywordforum.mydomain.com

If you use a subdomain for your forums the search engine would treat your forums as if they were on a diffrent website. I would receomend going with the www.mysite.com/forum