A system and method for tracking call activity of a plurality of businesses is disclosed. A global pool of phone numbers is allocated from which to draw numbers. A business-specific pool of numbers is established for business locations involved in advertisements using the Internet via Web pages. As a consumer begins viewing an advertisement for a business, a number is temporarily allocated from the business's pool of available numbers. As the business's pool of unallocated numbers is exhausted, a metric is used to determine whether or not to grow the pool of numbers, to show an untracked ‘fallback’ number for the business, or to reuse a previously allocated number. When one of the temporarily allocated numbers is called, the online consumer it was associated with is credited for making the call and the business is credited and charged for receiving the call.