Revenue attribution is the practice of tracing affiliate earnings back to the specific pages, links, and clicks that produced them, rather than viewing income as one lump sum.
Why it matters for your earnings
Without it you can't tell which content earns, so you optimise blind — attribution is what turns 'the site made $X' into 'this page and this link made $X,' which is where real decisions come from.
Go deeper: Guide: Affiliate Revenue Attribution