Thoughtsite is a discussions/forum app designed for Google App Engine. The main features of the app are:

• a flexible system that could be used for any kind of a discussion forum.
• voting, tagging, comments and a reputation point system for users.
• full text search on App Engine with Apache Lucene.
• search for threads by tags or by keywords. Threads can also be linked to from user profiles
• users gain reputation points based on community votes for their contributions
• full fledged user profiles with info, points, contributions, user's personal tag cloud, etc.
• basic duplication detection filters to detect similar threads so posters can avoid creating a new thread if one already exists
• basic spam and gaming filters (self-voting, cross-voting, etc.)
• full-fledged admin section that allows moderation of individual posts and users. Users can flag objectionable content or trolls.