Ask IH: OSS Social Network and Content Host for your family. Useful?

I find myself caring less about social media updates from friends these days and only really look forward to the messages posted in my family's Whatsapp group. I'd envisage this being a more fully featured and privacy focused version of that group.

It would be somewhere for your family to host images, plan events, share updates and subscribe to the updates of other families that you are close with.

It could be an open source product that you either host yourself or pay to have hosted for you.

It's nothing that you couldn't get from stitching together existing products, but I thought that by packaging it up nicely and emphasizing control and privacy you might be able to make an interesting product.

What are your thoughts?