Don't get me wrong with what I said before. I'm not advocating laziness in any way. I too, simply ignore multi posts of similar questions.
I can just see a parallel to this issue with, environment at work that's all. The difference there is that we're all working to the same end at work and so it usually much more cost effective to find your answer that way.
On the forums, we're typically not working ont he saem project and so the line is easier to cross.
But, hey, I'm a live and let live kind of guy. If there's a question and I feel I can answer it or offer a point of view and I have time to do so then I'll chip in. It's as simple as that.
I agree with what others have said but I've also participated/subscribed to enough forums and usenet groups to know that the problem will not go away either. There will always be people opting for the easy choice, ask a question rather than see if the answer is already there. I'm likely guilty myself on occasion, when I;m not talking rubbish answering questions...