"Craig Barth," the chief technology officer of Florida-based Devil Mountain Software, a company that makes and markets Windows performance metrics software, is, I have discovered, nobody. He doesn't exist.

Barth is, in fact, a nom de plume , which is a fancy, French way of saying "alias." The real man behind the curtain is , a popular, sometimes outrageous blogger for and frequent contributor to Infoworld , a publication that like Computerworld is part of IDG. Kennedy's .

The two, Barth and Kennedy, are one and the same. The problem was that I didn't know that. The problem was that Kennedy didn't tell me he was Barth, that I didn't figure out Barth was he, and that together, they were Devil Mountain.

Devil Mountain's data, derived from a network of PCs whose owners have voluntarily downloaded and installed a stripped version of the software the company has sold to financial service firms, Wall Street traders and government agencies, has provided some interesting insights into PC use and behavior: Internet Explorer is , or most recently, that machines are twice as likely as XP systems to . Barth's data was unique: Microsoft rarely divulges details of the telemetric monitoring it does on Windows PCs. Microsoft declined to comment or to make someone from their Windows or telemetry teams available for an interview, for example, to respond to the memory claims.

I have spoken with the man I knew as Barth between 15 and 20 times since December 2007. There was a phone number and a man behind the phone number. The guy seemed to know his technical stuff.