Another reason I'd be hesitant to change the 30 vote/day number is that the guys who built Stack Overflow did an extremely good job on the social engineering. Everything in the system is throttled for at least two reasons.
I suspect Scott would be in favor of thinking of it like an election. Since you're a good citizen, you should vote (let's say this means you should vote at least 10 times per day). You have to give those votes to somebody, so give them to whichever posts you think are most deserving. If you think all the posts are terrible, then you can still be a good citizen by downvoting!
One practical thing I find confusing is remembering whether or not I've up-voted a question before. I don't see anything different between a question I've up-voted and one I haven't (except for immediately afterwards, so if I come back to a question later then I can't tell). So I have a minor concern about trying to up-vote twice and whether that will actually cancel out my previous up-vote, be ignored, or cause mayhem
If you've voted a post up (resp. down), then the up (resp. down) arrow (the one you pushed to vote it up) will be bright orange every time you look at the question. You will never be able to vote twice on the same post, and you can only change (or take back) your vote within the first few minutes of casting it. Let me know if you don't get this behavior. I suspect you just don't come across the 11 things you've voted on very often.
]]>But really, I don't really have a sense of what makes a "worthy" question. As yet, I wouldn't say that there have been any really interesting questions. This may be because my subject area is a little under represented at the moment, but also because an interesting question for me has to be a) answerable but b) not immediately answerable. However, those aren't really good mathoverflow questions!
Maybe you should come up with some guidelines so that those of us unsure as to what should and shouldn't be voted up (can we come up with a better verb than 'up-vote'?) can use that to help us form our own rationale for voting.
One practical thing I find confusing is remembering whether or not I've up-voted a question before. I don't see anything different between a question I've up-voted and one I haven't (except for immediately afterwards, so if I come back to a question later then I can't tell). So I have a minor concern about trying to up-vote twice and whether that will actually cancel out my previous up-vote, be ignored, or cause mayhem.
]]>I think we're actually doing okay as far as voting goes. Almost everybody on the first page of users is above 250 rep and all the users on the second page are above 100 rep.
The one thing that I would emphasize is that if you're willing to spend your time answering a question, you should probably vote it up.
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