[halflings]

What new giant personal information are you giving, really? If you use Gmail, you already trust them with your emails and the interactions you have with these mails.

This features makes the experience better for users without having to give any additional information.

[pferde]

Yes, if you're using Gmail, you've already lost, but this IMHO inappropriately affects your workflow by steering your attention to, or away from, certain e-mails. To me, it's potentially no different from what Facebook was caught doing, and in fact, if done carefully, it is an authoritarian's wet dream.

Yes, you can (supposedly) train the "importance" filter, but how many people will do that?

[joshuamorton]

Literally everyone? It's trained based on the emails you respond to.