Of BT & Retargeting
As for BT & retargeting as a whole, there are two points I would make: 1) Contextual relevance is not as important as many make it out to be. Sure, it would be great to serve a $200 Off flights to California ad to someone who is looking at a page dedicated to wine country tour reviews. However, if someone has shown interest in a brand or product recently, they are just as likely to click on or be influenced by an ad if the content is unrelated. In my experience, CTR and conversion can actually be higher for retargeting when it is less relevant to the content the user is currently viewing.
2) To the [overkill] example, there is definitely a point of diminishing return for retargeting, not to mention basic respect issues. If someone does not frequency-cap their retargeting campaign, that is a fundamental error in my view.
Good article. Thanks!