Yeah, this was not great. I worry Google might do something similar with email and their attempt to curate it with Inbox and the growth of ads in Gmail.

They have the ability to control access and marketers currently pay a known fixed or tiered price for sending email to somewhat reliably reach their full target list (minus bounces). I'm sure Google is salivating over turning that into a dynamic auction based model with them as the gate keeper of one of the most widespread and valuable email clients out there.