Also, newbies seem not to be allowed to vote in polls, and also maybe can't create ones?
I think you actually need to have a certain activity level (maybe 15) in order to be able to vote in polls. I believe the threshold is below that of what is required to get out of newbie status but I might be mistaken
Not sure about creating a poll, but you need to be a jr member (ie. you need to have 30 activity) to vote in a poll.
https://bitcointalk.org/index.php?topic=606989.0Previously, anyone could vote in polls. Now you must be at least a Jr. Member. This should make vote manipulation more difficult, though you should still not rely on forum polls for real accuracy.