Interesting, we've also experimented with hosting git repos on Freenet, see: https://github.com/freenet/freenet-git
It is hard to grok what Contracts, etc. etc. allow you to do in the abstract so working through how it allows us to build a decentralized GitHub might be a good anchor in a tangible use case.
The freenet-git work is quite recent but we do feature River, our group chat app, fairly prominently on our installation page[1] so that people can quickly try out something useful. River is by-far the most fully developed app so far.
OK, time for inception... 9social on freenet-git
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