I have seen numerous examples of users who ask lots of questions, but almost never care to upvote any answers.
I think asking a lot and providing little if any answers is OK, but you should show your care for the community by upvoting some answers you like.
Is there a way we can encourage these users to upvote more?
Jeff - Is there a way to politely notify the user that he has upvoted very little? Perhaps something like the banner that appears when you've received new answer or comment? I am convinced that at least some of these users are not intentionally abusing the system, just misunderstanding it.