Having worked at Microsoft, and seeing the nature of the bureaucracy, the only advice I would give for next time is...
Just realize you can't set terms with a large company like MSFT unless you get lawyers involved early.
Stealing from you outright is simply too tempting, given their resources.
I noticed there were some conditions Keivan tried to set regarding the future evolution of the technology before joining MSFT.
In a large company like MSFT, there were bound to be large internal email threads relaying a play-by-play of negotiations with Keivan to: inside legal counsel, developers who already gave t-shirt sizes for building the tech in-house, product managers, and dozens of others.
No matter what they tell you, they're internally weighing
- Should we just rip him off? - Should we hire him? Would that be better or worse for liability? - How IP protected is this? How much can we "borrow"? - Is it worth the hassle of dealing with an aqui-hire we can't control? Would that expose us to even more IP risk, or less?
Once companies reach this size, they simply can't be trusted to handle a negotiation transparently and in good faith, unless you have well paid lawyers fighting for you, or well established IP protection.
I guess what I'm saying is...
When dealing with any large tech company with near infinite resources -- like MSFT, GOOG, etc --, find a legally defensible upper hand, and assume they are weighing the cost-benefit of screwing you.
(Sadly, this is exactly why lawyers make so much money.)
See https://news.ycombinator.com/item?id=23332123 elsewhere in this thread for an example of the consequences.
The cost of GitHub to MS was around 250 usd per user. If 4000 users leave that’s already a million USD.
Even in their recent history Microsoft has repeated incidents, but also has some very big positive milestones. Also, keeping in mind, some customers will only see the positive milestones.