We are an italian association with the focus on user privacy.
We are looking for a plugin (which we believe no exist in the world) that alerts the user when the mail comes from a big email provider as Google, Amazon, Yahoo, Microsoft, essentially all those structures that feed on our data even the most private ones!
This plugin should read the mail headers and show a simple alert to the users. For example a red warning similar to the spam warning, that the user can close (or not..)

And I come to the most burdensome part of the matter:
Anyone among you would like to participate in the creation of a such plugin?
Many thanks!
Davide