Certain types of merchants tend to get more phone orders, which always presents the problem of how to track and credit sales to affiliates. Here’s info about a new Pay per Call service. Press Release:

thinkingVOICE Launches Advanced Click to Call Service for Affiliate and Performance Networks “Whether marketing with Google AdSense, Yahoo Search Marketing, Commission Junction, Linkshare Network, Valueclick Media, or other ad solutions, thinkingVOICE new CallBeacon(TM) provides spending and conversion metrics for leads by phone. This opens a new era of performance marketing, a turnkey solution whereby advertisers may pay for calls driven by their affiliate networks and better understand marketing ROI”…

According to research firm The Kelsey Group, the market for pay per call advertising will more than double each year for the next five years with revenues reaching $3.7 billion by 2010. Call tracking is core to the success of pay per call advertising as evidenced by AT&T’s announced acquisition of Ingenio this week.”