What is Sub ID?

A sub ID is a parameter an affiliate appends to a tracking link so the network reports back which page, campaign or placement produced each click. It travels with the click and appears on the affiliate's statement. Without one, an affiliate knows only its total. With one, it knows that the review page earned and the listing page did not — which is the difference between improving the site and guessing at it. Networks name the parameter differently (stag, subid, sub1, sub_id), and some short links accept none at all. For a reader the relevance is indirect but real: a site that cannot attribute its own clicks cannot tell which of its recommendations people actually act on, and it has no data with which to notice that a page it publishes is sending players somewhere they later complain about.