Another promotional use of polls involves leading questions. By producing an artificially high/low number in support of a particular policy you can push the media to:

(a) reopen a debate

and/or

(b) start building rationalisations for why people feel so strongly about the issue and why other polls didn't show this before.

Now, this approach isn't always successful, but especially as part of a broader campaign it's a good way of poisoning debate.