So, this comes up every now and then on #Nostr: running a relay on your phone. It's probably not super practical for using as a conduit for sending out to the network, but you know what it could be useful for? 

Storing a copy of your social graph locally. 

What if someone designed an NSec Bunker-like experience, where identity, and content management, auth, and storage all live in your device?

I started off thinking about this in the context of how limiting Fediverse servers can be, but I think it could suit Nostr. You could even set it up to import and translate data from other services, like your Facebook or Medium exports. With the right mechanisms, you could even sync it from one identity to another, somewhere else on the network. 

Am I crazy, or does this have legs? 

 I’m pretty sure all of these things have been done already at least at the prototype level.