what does "effective" mean, in communication? there is a goal orientation implicit in the question that seems to negate the qualifiers that you include. (ie, if you know you want to go west, then there's nothing necessarily wrong with people telling you that you're not going west).
but it's highly likely that online, pointed conversation (discussion for the purpose of coming to a conclusion with at least one other person online) requires (either tacitly or explicitly) agreed-upon goals, as well as a vocabulary in common. (which doesn't mean, by the way, that people can't use words that the other(s) don't understand, but that there are some basics that are agreed on. cultural similarity would be another way to talk about it.)
and then, there's my fall back position, which is that there is no reason for us to pay attention to anything in these online conversations except what is helpful to us. and since no one but us can determine that, there is no reason to avoid the bullshit. (although it's true that sheer mass can be a reason to act, at some point.)