There is a matter of semantics with certain publishers that will saturate some of the true value of employing a retargeting advertising strategy. If a single network is offering a retargeting ’solution’ as a package offering with other display, some sort of CPC, etc., I’d be wary of their temptation to retarget on the click rather than the visit for the sake of impression scaling.

What’s the difference?

Any groomed Google Analyticsman will tell you that a click does not equate to a visit (1-1). There can be pre-page load bounces, multiple session counts, spiders/bots, fraud, and who knows what else muddling up your clicks. If a user is not arriving on my site after clicking an ad, I do not want to waste impressions on them. Call me old school, but behavioral retargeting must be site-based to be effective.