The "$650 for $6" part is a bit disingenuous. That's what you spent showing banners to people that saw your site and eventually converted. You might have gotten

The "$650 for $6" part is a bit disingenuous. That's what you spent showing banners to people that saw your site and eventually converted. You might have gotten that $650 without spending a single dollar if they were going to convert anyway. It's not unusual, especially in B2B, for someone to convert days or weeks after the first visit. You probably also spent more than $0 acquiring some of those visitors to get them on the retargeting list in the first place -- retargeting doesn't bring anyone new in. What needs to be compared is conversion rate with/without retargeting (i.e. retarget only a portion of the same traffic at the same time), and whether the added conversions, if there are any, bring in more revenue than it cost to do the additional advertising. That's something you can measure rather than guess or speculate based on anecdotal feedback. Not to say that retargeting isn't probably working out for you. I use it as well (also with Perfect Audience, they're great). But I have also wasted enough money on ads that felt like they were working but really weren't that I take the time to measure results now. For example, I don't retarget every visitor to the site. Only hitting people that viewed the pricing or signup pages works just as well.