"The premise behind pay-per-call is that not every company is prepared to measure clicks. Some that currently participate in search engine marketing are in over their heads, some are too intimidated to begin with, and others still don't have a Web presence to speak of.
Here's the gist of how it works. An advertiser enrolls online, listing their phone number, description, market (e.g., city, miles from ZIP code, national), categories where the ad should appear, the bid price-per-call, and daily budget. Ingenio assigns a unique toll free number to each advertiser, and this number is displayed prominently in the paid search ad. Calls are forwarded to the advertiser's original number. The highest bid nets top placement in search results.
Ingenio is the pay-per-call company. Right now, they can rightfully be referred to as the pay-per-call company since it's the only known entity in the space. Ingenio isn't only a pay-per-call company - it's been in business since 1999 and has a number of other technology solutions, platforms, and services. According to Barach, pay-per-call is now the locomotive powering Ingenio, and everything else is along for the ride."