Occasionally a "feel" for consensus is not enough. Sometimes we need to have a measurable consensus. For example, when voting in new committers or to approve a release.
Before calling a vote it is important to ensure that the community is given time to discuss the upcoming vote. This will be done by posting an email to the list indicating the intention to call a vote and the options available. By the time a vote is called there should already be consensus in the community. The vote itself is, normally, a formality.
Once it is time to call the vote a mail is posted with a subject starting with [VOTE]. This enables the community members to ensure they do not miss an important vote thread. It also indicates that this is not consensus building but a formal vote.
The notation used in voting is:
If you object you must support your objection and provide an alternative course of action that you are willing and able to implement (where appropriate).