What features will such a platform have? What modules provide these features? And what work is needed to wrangle these modules together?

Social networking

• Who's your friend? Who's just watching you?
  • modules: Buddylist, Relationships
    • User relationships looks great, but seems very incomplete (at least in Drupal 5.x)
• What are they doing
  • modules: Activity for onsite, Activity Streams for offsite

Discovery

• Who is like you?
  • modules: Neighbors
• What content is like this content?
  • modules: Similar, Related Content
• What content would you like?
• What groups would be of interest

Groups

• modules: Organic Groups, OG forums

Sandbox a user's content

• Make monthly archives, tags, related content, etc for a single user AND for the group
• Learn something from og.module on this?