Every time I read something about Urbit I am reminded of the Lewis Padgett short sci-fi story, "Mimsy Were The Borogroves" [0], [1] describing children discovering alien future toys, and subsequently via use of those toys learning to manipulate reality in incomprehensible ways. I still have not been able to figure out if there's actually something that amazing about Urbit, or if behind the obfuscated terminology ther…
I'm one of those people that get it, so I'll try to explain it without going off the deep end and waxing poetically about planets or whatever. Urbit is a platform for building decentralized apps. To that end, it's a tightly integrated set of different features that play into that: an identity system so that all the apps can refer to the same people by the same handle, a typed RPC network for easy message sending, and…
But of course, that's not all it is.
It's also a ground-up reinvention of mainstream functional programming languages like Lisp, built on the foundation of an abstract virtual machine in which the "decrement" operation can be performed natively only by incrementing a number until it's 1 less than the current number. All of these concepts have their own weird names; for instance, the constant-time version of "decrement" (this is a programming environment that goes out of its way to achieve constant-time decrement†) is an example of a "jet", where a jet is apparently a non-native implementation of an algorithm that can be expressed but not efficiently on the VM that they've chosen to build their entire system on and it just gets weirder and weirder from there.
You don't have to memorize the new names they've come up with for most of the ASCII punctuation characters, like "gal", "gar", and "hax" for "", and "#", "but it helps". A normal engineer's reaction to a system that tells it that it will help to remember a new name for the pound sign is to ask "Why? What fresh horror lurks in the deeper meaning of your new name for the percent sign? And why won't you tell me before I commit to this system?"
Stuff like that would be bad enough, but the founders ideological views are also infused into the system, and those views are not mainstream distributed systems engineering views. For instance: the most available first-class address in the system is in a 32 bit address space. Why? Not for efficiency, but because the authors believe there aren't and never will be 4 billion human beings on the planet worthy of having a first-class address in their system. This, by the way, is their actual response to the objection of an overlay network with 32 bit addressing.
I agree that the best way to explain this system while encouraging people to engage with it is to distill it down to anodyne concepts and then sprinkle "decentralization" on top. But of course, this system isn't really that. From the proteins of its cell membranes to the DNA in its nucleus, this is a system that coercively projects the idiosyncrasies of its founders into everything it comes in contact with. It's decentralized and free in the sort of way its founders would explain with a 3000 word paper that invented 50 new terms in its abstract.
People confused about Urbit are probably not confused about the value of serverless computing or of overlay networks. Those are pretty straightforward concepts we can all get our heads around. There is something deeper that is challenging about Urbit.
† Rather than, you know, just deciding to have it.