It shall point to http://www.minibb.com/forums/
, not to http://www.minibb.com/forums/index.php?
Search engines consider these two to be different pages. In today's "world of links", if you point one to the first and second to the second, it will not bring you that high in search results, as if you would give both two links to the first (or to the second). (Simplified reasoning.)
This is the same reasoning as for my first post in this thread. Say I'm writing a review about minibb and want to tell users how to change their logo after install. So I search for "How to change the picture at the top of forum", following comes up, http://www.minibb.com/forums/index.php?action=vthread&forum=7&topic=20 82,
and it is the one that I will give a link to from my page.
However, that's not as good as if I would link directly to http://www.minibb.com/forums/7_2082_0.html
Not even speaking here about duplicity issues (will search engine count the first link?, because obviously if the second url is indexed, it might consider it duplicate content), as I am not well versed in them.
The point is in watering down the power. If you get two links to page x, will get you better search engine results for that page, than if you get one link to page x and another to page y.