A specification can be associated to a distribution or a product by anybody, but only the drivers can approve the targeting of a spec to the series or the release. What that means is that any member of a community, authorised or unauthorised, can document their own planned feature in the Launchpad listing for a product, or a distribution.
But only the drivers of a series or distribution release can approve that feature as a GOAL of the series (or release). This allows the project managers to keep a tight lid on the set of features (and, as it happens, bugs) that they will try and manage for a given major release.
Nominating a Feature Goal
Anybody can nominate a specification as a feature goal. If that person is a driver of the series/release then it will automatically be approved as a goal, if not, it gets given the "Proposed" status and the drivers can see it in a special listing for the series. They can choose to approve it, or decline it, as a feature goal. You can always call up a list of the feature which were declined for a series/release, just click on "Show Declined" in the actions menu of the Blueprint page for that series.
Approving Feature Goals
If you are a driver for a product series or distro release, you should periodically check to see if there are any new features proposed for that release. Go to the series or release page, and click on "Set Goals" in the actions menu. You will see a list of proposed specifications, if there are any. Check the ones you wish to approve or decline, and press the relevant button.