What you say is mostly correct but I want to fix a few of your statements and assumptions. Regarding the skepticism on the end results of retargeting I can say

What you say is mostly correct but I want to fix a few of your statements and assumptions. Regarding the skepticism on the end results of retargeting I can say that all the transparent retargeting companies offer you A/B testing of your retargeting campaigns. What we do is show PA ads to a control group and your retargeting ads to the experiment group. What we see is a lift of conversions between 40% and 200% and CTR doubles at worst compared to non retargeting display campaigns, these numbers vary by industry but are a good representation. Google has moved its entire network inventory to the Google Ad Exchange. What this means is that for every impression there is an auction in real time where multiple buyers bid in real time for the right to show an impression to a specific user. While it's true that Google might filter out impressions that they deem particularly interesting for them it is not what we are seeing on the exchange. AdRoll.com adheres to both Do Not Track and to the AdChoices initiative. Both of these allow the users to opt out of all retargeting campaigns either from their browsers or from the Ad itself (through the AdChoices icon). More information regarding this initiative is at http://www.evidon.com http://www.evidon.com. Disclaimer: I work for AdRoll.com and we are the biggest self-service retargeting platform.