You wrote John doe <Johndoe@gnail.com> did you mean
<johndoe@gmail.com>
This giant contacts list, shows public listings that
spammers have, and your own listings can be uploaded
(staying private without going public). You can publish your
email address as public or private.
You can prove
that an email is yours and you can remove
yourself from the list. It could help you find correct
domains.
The other half of baking is how to keep it away from
spammers. (Perhaps its a service only available to
established users. And if people complain the spammers
could be tracked down.)