I am quite an old guy here on askubuntu.com, and I think that most of us have a problem with upvoting questions. If you see other communities, like tex.sx or photography.sx, you can see a quite different pattern there: questions have on average much more upvotes, and a highly voted question is often a question worth reading --- independently on the fact that it could be a question representing a common problem or a rare, complex one.
That can be because we have an awful lot of silly question --- or because people that answer questions is getting lazy. So I suggested the following:
If a question is worth the time to be answered or commented on, it should be upvoted.
If a question is worth the time to fully read it, and you understand the question but don't know how to solve it, you should upvote it.
On a "main page" shot today, there are lots of question with answers and with a total zero upvotes. This is simply illogical.
Moreover, when browsing the site, we should normally upvote interesting question and (if available) what we think are good answers. That will help visibility, lower duplicates, and it will be good for everyone. In that aspect, https://tex.stackexchange.com/ is quite exemplary --- duplicates are so low because the people there have a very nice, effective voting policy --- and the right answer pops up alone.