One of the pieces of infrastructure that makes all kinds of networks work and yet gets very little attention is the directory. Directories are big business. For example, there's directory of telephone numbers run by NeuStar, Inc. NeuStar has annual revenues of $92 million. Now, accoring to Light Reading, AT&T Corp. and MCI Inc., together with unidentified cable companies, telephone companies, and ISPs are preparing to form an LLC that will run a process to define a new company that will run ENUM.

The ENUM directory is the infrastructure that will link phone numbers to URLs, and thus IP addresses. ENUM is crucial to the development of widespread VoIP services. The ENUM directory promises to be more lucrative than NeuStar's business, so I'm sure there will be some hard fought competition to win the ENUM contract. In general, I think there's missed opportunity in directories and not enough businesses fully develop the potential of the directories under their control.