My co-founder and I are building a groups and events system (like Meetup) that has a friends list and things like instant messaging. Our business model at the moment is freemium with ads and a limited organizer experience (you can create small groups/events) or we are offering a small subscription ~$5/mo. The subscription model removes the ads, unlocks all organizer features, and removes all limits on organizing groups/events such as being able to create a hierarchical organization with the tooling to manage it.
We are currently in YC Startup School as Geddy at geddy.io and we plan to launch soon.