"With so many guides on editing online content, it's almost impressive how many bloggers and social media writers manage to ignore that aspect.
They keep posting draft versions that make real readers lose their interest after few sentences."
Mindjet MindManager Pro - commercial software for mindmapping, with online collobaration, integration with MS Office, PDF outputs, Gantt Chart integration, a web side, and copious features, templates etc.
XMind is opensource mindmapping software, with a Pro version also. There are drilldown, workgroup and multiple sheet functions and the audio notes make this appealing for collobarative mindmaps.