I don't think the issue is as much with the clients as it is with the spam filtering Google provides. The sheer volume of emails they handle allows them to have the best spam filtering in the world. Something, that will be very difficult to duplicate through OSS.
This is very peculiar. From past Dropbox acquisitions, one can extrapolate they're almost certainly working on online collaboration tools. I wonder if Dropbox is using this as a way to gain footholds in large enterprise.
It's actually pretty easy once you realize that you have to pay for the licences on all Microsoft technologies once BizSpark ends. It gives just enough time to be too locked in to easily adopt a different technology stack.
I've been told by family anecdotes that Pepsi & Coke were a prized possession in the USSR. Whenever they were able to acquire a bottle, you would never throw it out immediately after finishing, but rather refill it with water as there was still some residual taste.
The main takeaway was work as hard as you can (i.e. 80 - 100 hour weeks). Even if you're doing the same thing as the competition (assuming they work 40 hours), you'll still accomplish in 4 months what they would in a year. Hard work, tenacity, and a little luck is what separates the smart from the brilliant.
I feel as though this is one step above just a web page with an email box. Aside from listing a suite of popular OSS, you haven't explained what this app does. Is it similar to Panamax in that it offers you a UI, but only for one box / Flynn or Deis which is trying to create an open source Heroku / something completely different?
I've seen their hard drive reliability blog posts, but I never knew they were so open about their storage server designs. I think it's really cool how open they are about something that is definitely a competitive advantage.
From a sideline viewers perspective, persistence in production for Docker containers is a big problem that I've yet to see a good solution for. You end up having to keep DB servers and such outside of your container pool.