Ok... after reading up on this since I wrote this message, I've finally found out that, despite this being the first thing said on their website:>A personal server is a virtual computer which stores your data, runs your apps, and manages your connected devices.>Urbit is a secure peer-to-peer network of personal servers
they do NOT, in fact, offer any sort of Virtual Private Server! All that talk about "hosting apps" and such - you're supposed to Bring Your Own Device!
What the hell? Ok, a free VPS is, perhaps, a deal too good to be true... but I figured the very-limited VM was the trade-off. Sure, I'll live with whatever disk quota you assign to me, and I guess I can learn a new language in order to develop apps... but it's a "personal archive, application platform, and device hub" - all without an archive (no storage), without a platform (no machine to run your esoteric code) and "a device hub" only if YOU actually bring in devices and run the application on them.
So... what's left? What is it, really?
Well, currently, it's a namespace, with the idea that a planet == a person (as I read in an Urbit rep's response). The problem with that is, planets are capped to the same number as IPv4! There's an AMA on reddit's /r/urbit, and they say "isn't it more like 3 billion?" in reference to Internet-connected people. Oh sure, you're not on the Wired, you don't exist, the coverage isn't expanding (o3b, for instance) and more people aren't being born. So that basically invalidates it as anything meaningful.
I was really excited to see that someone was FINALLY bringing cloud computing to the masses! But, with no tangible product (no server), I'll pass on joining for the joy of developing applications in a new language, hosting them myself, and getting a subdomain.urbit.org hostname for it (when I can use subdomain.dy.fi for free, to get that same result).
"Your urbit is your own general-purpose server." -- NOT!