This is interesting but as pointed out by other comments there is great danger of Gmail abusing their position to make life harder for small email providers. I

This is interesting but as pointed out by other comments there is great danger of Gmail abusing their position to make life harder for small email providers. I would be more positive towards this if they gave precise, technical details of their notion of "supporting TLS" and "being authenticated", ideally with a service allowing me to test easily whether my mail server is fine according to them (rather than having to sign up for Gmail to test it).