Adobe Experience Platform Identity Service is the more common of the two in our index: it runs on 815 websites against 14 for Klaviyo Data Platform. Counts come from real scans, not vendor claims.
Adobe Experience Platform Identity Service creates identity graphs that hold customer profiles and the known identifiers that belong to individual consumers.
Klaviyo Data Platform is Klaviyo's CDP offering.
Want to know which one a particular site uses? Look it up and see its whole stack, or compare two sites side by side.