@noffle great work, I also hope it's gonna be in patchwork or thelike!
But I guess it's gonna need a fair bit of other work, too, to make it really useful, no?
Because at the moment, you can "only" publish a website once, then never update it, right?
What I feel is lacking in ssb-land (and what you also mention) is an up-to-date source of information. Threads age and get hard to find very quickly. And the only place I see where I could collect some information in a way that other people always know where to find it would be my profile information...
So I guess ssb (clients) would have to learn a "diff" or "update" message that modifies an old one? Then it would come down to client-side presentation so that the user knows the message has been edited, and can go through the history if necessary.

Anyway, great work! :)