I'm probably not the only person getting a bit mixed up in the forum interface. There is hierarchy of topics, replies and comments, which I will try to explain. Effectively there is an extra 'level' compared to the original forum:-

Original Velo Vision Forum : Lists e.g. "VV advertiser offers"
-> Individual Subjects e.g. "UNDER OFFER - Nazca Fuego - large edtion"
-> replies

New Velo Vision Forum : Fora e.g. "WEBSITE FEEDBACK" is a 'forum'
-> Individual topics e.g "topics, replies and comments"
-> replies
-> comments

Whether you add a reply or a comment depends on which text box you write in. It appears that you can only write a comment against your own post or reply, so you can regard comment in the same way you may write a P.S.

Note that, comments are not listed in RECENT FORUM POSTS AND REPLIES