..I would let you (heroku) do that for me, magically? ;)

Wouldn't that be nice!

I work on Heroku, on the databases, which are rather thorny in that department...

...it's going to take some evolution in how applications are written to make that work not uglifically (and it'll probably be ugly at first and for a while), but it's the dream, and I think it'll come to pass over time and with work from many people.

There are literally more Heroku folks in this thread than unaffiliated commenters :P well played.

Personally I'd just be happy with a master-master postgres db or sharding, for $money, where money is some amount enough to make that happen without me worrying about it.