Retargeting
Retargeting shows ads to users who have already interacted with your brand — site visitors, cart abandoners, past buyers — using pixel or CAPI tracking. Usually the highest-ROAS slice of a paid media plan.
Retargeting is mechanically simple: capture an identifier when a user visits your site (Meta Pixel, Google tag, CRM email hash), build an audience from that identifier list, show ads to that audience on Meta / Google / LinkedIn. The ads typically reference the specific page, product, or intent the user showed.
Retargeting is where beginners often go wrong on incrementality. Reported ROAS on retargeting campaigns looks spectacular — 10× or higher — because the audience was already going to convert. Holdout tests usually show iROAS much lower, sometimes under 2×. You don't want to kill retargeting (the incremental lift is still positive), but budget allocation should reflect incremental, not reported, return.
iOS 14.5+ and third-party cookie deprecation have degraded retargeting precision. Workarounds: server-side Conversions API for Meta, enhanced conversions and Customer Match for Google, and server-side CRM syncs to replenish lookalike + retargeting audiences.