This looks great, in typesystem/tooling/presentation, and sounds perfect for facebook; but for mainstream adoption, it needs to meet (or be closer to) the ideal

This looks great, in typesystem/tooling/presentation, and sounds perfect for facebook; but for mainstream adoption, it needs to meet (or be closer to) the ideal of free-benefits: (1) zero-work: works instantly with existing code and esp third party libraries; and (2) instant-benefit: provides some compelling benefit in that zero-work case above (of course, it's OK if it provides more benefit if you do more work, adding type annotations etc).