SubID

A SubID is a custom parameter appended to a tracking link that lets you tag and later segment traffic by placement, creative, source or any dimension you choose. Each click carries its SubID values through the tracker, so when a conversion fires you can trace exactly which zone, ad or audience produced it. It's the granular labeling system that makes optimization possible.

Buyers pass multiple SubIDs at once — one for the site zone, one for the creative, one for the audience — then cut losers and scale winners by reading conversion data sliced along those tags. The common mistake is passing too few SubIDs and being unable to isolate what's working, or dynamic macros that don't populate, leaving every click labeled identically. Plan your SubID scheme before launch, not after.