Directory assistance is the largest available enhanced calling service afforded to subscribers. What started out as a simplistic, logical customer service feature has metamorphosed into a volume intensive multi-billion dollar industry, generating an entire sub-industry of third party providers and product complements. Directory assistance service is available to almost every wireline subscriber, wireless phone customer, and persons that can access the Internet. In 2001, there were approximately 7.35 billion executed listing searches completed by directory assistance providers.