David Petraeus shakes hands with author Paula Broadwell. (Handout/Reuters)
Retired Gen. David Petraeus might want to think about following his own advice.
The former CIA director, who quit his post on Friday after the FBI discovered he was having an affair with his biographer Paula Broadwell, once warned about the dangers of a digital data trail.
[Related: White House: Up to Congress whether Petraeus testifies on Benghazi]
In March, Petraeus spoke at the In-Q-Tel CEO Summit. His speech addressed, among other things, how online privacy and security is, in today's day and age, practically nonexistent.
... we have to rethink our notions of identity and secrecy. In the digital world, data is everywhere, as you all know well. Data is created constantly, often unknowingly and without permission. Every byte left behind reveals information about location, habits, and, by extrapolation, intent and probable behavior. The number of data points that can be collected is virtually limitless-presenting, of course, both enormous intelligence opportunities and equally large counterintelligence challenges.
His remarks now are bitterly ironic. Petraeus left a digital trail of his affair with his biographer Paula Broadwell, which ultimately led to his resignation. FBI agents who were tasked with tracking down the origin of the harassing emails reported by Jill Kelley (and were allegedly sent by Broadwell) used "metadata footprints left by the emails" to determine their origin, according to The Wall Street Journal. In other words, Gen. Petraeus probably wishes that Broadwell had heard—and that he had heeded—the words of his speech.