Thanks to VoxPolitics and Tom Watson MP for pointing me to iCAN!. It's still in beta at the moment but I think has great potential as a campaigning resource for communities.

If (once) it takes off this sort of thing can potentially have a big impact on PR. It gives disgruntled customers or stakeholders another forum to work with. It also has the potential for use in astro-turfing campaigns. This is where a company or special interest group will whip up a 'manufactured' grassroots campaign.