> In the DB, we have a groups table and a group members table. Each
> group can have an owner. Would you state that the owner is in the
> group members table (with a group_membership_type attribute) OR would
> you say that it is already implied by the group_owner attribute in
> the group table?

Will you ever want two or more group owners per group? If yes, then you
need an extra table for that. It is an open question whether to reuse
the group_members table or create a group_owners (wich much the same
structure). Usually I would consider the latter a better solution.

> Also, can a topic be considered a post or are they two separate
> things?

Could be either, depending on what forum structure you are aiming at.
These days, forums with topics and posts are more common, but you can
still encounter post-only forums (usually the forums with tree-like
structure are post-only, while "flat" forums are topic-post).

Pepak