DNI
DNI (dynamic number insertion) is a call-tracking technique in which a website shows a different phone number to each visitor depending on how they arrived: the ad, campaign or search that brought them. Calls can then be attributed to their source.
Also called: dynamic number insertion, call tracking numbers, number swapping
A pool of tracking numbers is reserved, each forwarding to the business’s real line. When a visitor lands from, say, a paid search ad, a script swaps the displayed number for one assigned to that visit. When the call arrives, the number dialed reveals which campaign, and often which keyword and session, produced it.
DNI is how marketers work out cost per lead for phone-heavy businesses, where the conversion happens on a call rather than a form. It needs enough numbers to cover concurrent visitors, and the swap must not break the number printed on business cards or in Google listings.