From the website:
What is Open Assembly?
OpenAssembly is a non-partisan site that looks to revolutionize the collaborative power of the internet. OA allows users to brainstorm a democratic platform, argue the ideal course of action, and reach consensus on those actions. These features were fully functional in the previous design, and we are using your feedback to reinegrate them into our new innovative design.
* Discuss: Open Assembly features a forum where you can discuss issues that are of interest to you and deliberate over the pros and cons of those issues
* Vote: Express yourself by declaring both your subjective agreement on an idea and your opinion on the objective quality. No longer must you upvote a poorly written idea that you agree with.
* Decide: You can make timed decisions or poll the group. Rank the nominated proposals to identify and focus on the best or accept all the solutions the group suggests
* Configure: Set the consent and reporting requirement that works best for your group, from traditional majority rule or complete consenus.
Open Assembly is open-source software and its source code is on Github.
Update: Open Assembly has been discontinued. In order to access the site, view an archived copy.