It has started with the tabs, you are right. I don't think introducing ads into the feed is as ludicrous as you say from a business standpoint. If done properl

It has started with the tabs, you are right. I don't think introducing ads into the feed is as ludicrous as you say from a business standpoint. If done properly, I could see Google avoiding a mass exodus while simultaneously opening up more inventory for them. In some ways, I see Inbox as a test towards this vision. My broader concern is a fundamental shift in the ownership of a customer/user relationship and the cost of reaching them. In today's world, you pay a fixed price for your ESP, and then some CPM rate for volume typically. Your costs are known, often negligible, and entirely under your control. Likewise, as long as you follow best email practices and nurture healthy relationships with those on your email lists, you have an expectation that your email will land in their inbox if they want to receive it. That is similar to what FB had back in the day when someone Liked your brand page. If you posted, they would see it assuming they scrolled through their feed enough. My fear is that Google will change that dynamic such that you cannot be guarantee to reach your audience (even if you have great deliverability) without entering into an auction and paying a constantly changing price that presumably will always increase as they maintain control as the new gatekeeper of that customer communication.