I just replied one comment in one thread at https://groups.google.com/forum/#!categories/google-admob-ads-sdk/android
And after that my Gmail account started to receive next emails (email's Subject contains the name of this thread at Google Groups):
Is this a joke? I've received such email 4 times
I've never used BitBounce.
I don't know... mb Google Groups Site uses my email to notify other users (I don't if those emails are emails of users from that thread, though it would be weird if all of them used BitBounce)
If it's true then why Google Groups dare to use my email? Because of it I get all these annoying spam messages