Audience Signal is information supplied to automated campaigns to help machine learning understand likely converting audiences.
It matters because paid search can spend budget quickly. Knowing this term helps teams control intent, targeting, bidding, creative, conversion tracking, and lead quality instead of optimizing for surface-level clicks.
Example
A retailer supplies a relevant customer audience as a Performance Max audience signal. That gives the system a useful starting point, but it does not limit delivery exclusively to those people; the advertiser still evaluates the campaign’s actual customers and conversions.