There's probably a segment of small mid-sized businesses to prey upon making apps with this; but outside of that this has got to be the most terrifying platform to ever build upon.
1. It's based on a specific email provider.
2. That provider is google.
3. Google has zero incentive to give a shit about about anyone or anything using its platform.
4. Average SDK releases per week: 12 (screw the fact GMail hasn't been responsible for breaking changes)
Focusing on a tool that does this shit, on any platform, or one that integrates into any email provider... that'd be neat. This I am afraid of...