1. You have to be logged in as an LJ user to vote in an LJ poll. "Open to: All" translates as "open to all LJ users"
2. You do not have to fill out a poll in order to view the results.
2a. Click on the poll number. Then click [ View Poll Results ].
2b. wisdomeagle informed me that you can just null-vote by clicking Submit without having filled anything out in the poll.
3. You can change your votes after submitting (though I know of no way by which you can change a radio button vote to a null-vote, though you can undo check box votes). From anywhere within the poll, click [ Fill out Poll ] and change your submission. (Just remember to click "Submit Poll" when you’re done.)
4. Polls can only be created by paid users.
5. Polls cannot be edited after they are created. You also cannot paste poll code into an already existing entry.
6. You can limit voting to your flist, though there is no filter option. Ditto viewing results. You also have a "results viewable to: None" option. Everyone will still be able to see the statistical results, but only the poll creator will be able to see individual people’s answers. (Clicking "View Answers" within the poll shows you each person who voted and their answers. Though if it’s a multi-question poll you have to view each question individually.)