Jordan--
Of course you can reply to postings -- that is the whole purpose of this board!
If you're on the message-board home page and look at the descriptions of each of the forums, you'll note that the "OCF Cancer Blogs" forum -- and only that forum -- does state that postings "are not to be replied to by others." Perhaps Brian, Gary or one of the other old-timers can explain why this request was initially made.
That said, that request has been widely ignored, and some people who started threads there have said they welcome comments. If you have a question about whether your reply to a posting on the OCF Cancer Blogs forum would be welcome, you can always e-mail or send a private message to the thread's originator.
On all other forums, post away!!
-- Leslie