MediaSilo is an online video collaboration tool that has just opened its services to the public.
MediaSilo is designed for business use, so teams can work together on video projects. This feature-rich service enables a high level of customization and collaboration for team members. All uploaded clips are saved as versions and converted, minimizing the need for team members to download plug-ins or worry about codecs. Clips can be annotated and tagged, and these notes can be exported to a spreadsheet. Administrative functionality is extensive, including an "electronic signature needed" for final approval of certain clips. MediaSilo will work well for material you may be working on for a client: they can review progress and leave their own feedback as well. You can also create your online TV channel with MediaSilo, which is managed using drag-n-drop capabilities.
This isn't necessarily a community for video editing, but you can easily embed your video into your own website. MediaSilo is a paid, subscription service and will run you about $99 per month for the most basic plan, but for those companies that are heavily involved with online video, this may be a viable enterprise solution. Track your audience behavior with MediaSilo stats, or utilize their API to offer video collaboration within your service. The collaboration initiatives are rather involved and are probably moreso than Mogulus, though MediaSilo doesn't appear to have real time, live collaboration for multiple users, as Mogulus does.