You know.. I've always had something against salaams.. It sounds odd.. Like "peaces be upon you". Ahem.
Another interesting thing is that when we address a number of people, saying salam is wajib if there are muslims amongst them, right? Even if some reading/hearing it are non-muslim.
Therefore, wouldn't it be wajib from this position to proffer these when initiating a discussion/making a first contribution to a discussion?
But once engaged in the discussion at hand..