Before I ever asked anything on SO itself, I was active on TeX.SX . My experience there is that valid questions, which are clear enough and not missing relevant data, most often get at least 1 up-vote; and that answer-providers often up-vote the question if it's a 0-vote or sometime even if it's a 1-vote question. You could say the logic is "if it's worthy of my reply, it's worthy of not being a zero-voter".
Now, TeX.SX is a much smaller site/community of users than SO itself. And yet, here, it seems that questions have a harder time getting any upvotes at all. Is this just my impression or is there more of an upvote stinginess in the SO culture? And, more importantly, is it not worthwhile to encourage voting over 0 as a means for 'vetting' a question?
Edit: See also this answer to the related question on How come so few SO questions have an answer accepted.