We need to recognize that each user has a right to try to influence policy in ways that they believe are beneficial to the project. Two basic tenets of this are discussing the ideas and building up groups of people who agree with you and who will help you bring about the beneficial change.
This is "advocacy". Contacting people to recruit them to support you or to act according to beliefs you think they may already have should rightly be called "campaigning". This is a Good Thing.
Let's stop insulting people by calling them "meat puppets" or "vote stackers". Let's stop confusing the issue by calling it "spamming". It is not spamming. Spamming is indiscriminately notifying people that are probably not interested in the hopes that a few people will be. This is practically the opposite.
Attempting to stifle advocacy is harmful to the consensus building process and it is harmful to the project. If we try to prohibit it, it will just be taken off-wiki, which would be a huge shame. Johntex