Urbit Questions

A few questions that I have been wondering about with regards to Urbit:

• Privacy. How does privacy work in Urbit? If most interactions are P2P and packets emit from my planet, wouldn't metadata be extremely revealing? Even if the packets themselves are end-to-end encrypted? How much of an issue is that? How can privacy of Urbit users be protected?
• Security. What happens if my planet gets hacked. At some point, if that's the main computing platform people use, it seems like a hack could have disastrous consequences. How can one recover from hacks?
• Closed-source software. Is it possible to distribute closed-source software to run on people's planets? If yes, what are the main differences to the traditional paradigm of me buying some closed-source software that runs locally (e.g. Microsoft Word)? If no, wouldn't that keep people locked in partially depending on cloud?
• Business models. What are the new business models that are enabled by Urbit?
• Application distribution. An obvious and large opportunity would seem to be some kind of app store. How can I find new software to run on my planet? How can I know it is secure? How would such an app store work?
• Mobile. Can you build a mobile operating system similar to iOS / Android with Urbit? What are the main challenges with that idea?
• Crypto. What are the things that we imagine to run on-chain that could actually be better run as applications on someone's planet? What is the interplay between Urbit and blockchain / cryptocurrencies?
• Use cases. What are the most compelling use cases for Urbit? What are the things that Urbit does uniquely well and that could get a lot of adoption early on.
• Hosting. Is hosting an interesting business? Or is it just a commodity thing, where you just automate some deployments and maybe backups on top of normal cloud. What are the dimension on which different hosting providers would compete?