[Mahh]

The fact here isn't quite right. (I'm an employee at Dropbox)

Primarily, until 2 years ago we did lean on S3 for all block storage, but most of the rest of the infrastructure (metadata storage, etc) ran in our own datacenters.

Your point I think you're getting at sounds like something I'd agree with though -- you can wait a bit the cost efficiency starts to be what is important/impactful to work on before shifting your usage away from some of these providers.

[late2part]

I heard a story once that Dropbox started to move their data out of S3 and AWS rate limited them so they couldn't.

I don't know if it's true or not but I heard the story.