The man whose agency secretly gathered up millions of Americans' electronic communications for years without their knowledge admitted Monday that he has no idea what Pinterest is.

The disclosure gives some indication as to the limits of the NSA surveillance programs disclosed by former government contractor Edward Snowden (is Pinterest firewalled at the NSA?) In an interview that aired Sunday, retired NSA director Gen. Keith Alexander gamely played along with comedian John Oliver's meandering rant against Pinterest users. Until he couldn't.

"They are the worst people," Oliver said. "'Oh look, I've found this gopher bedspread! I'd love that.' Shut up. Shut up."

Alexander chuckled awkwardly before dropping the ruse and admitting, "Sorry, I've not seen that."

The two men had been (humorously) discussing changes to the Internet that would make the NSA's job easier -- such as dividing the Web into spaces that contained only evil people. Oliver leapt at the opportunity to lump Pinterest users into the category.

"That seems to be where they kind of assemble," Oliver said to a bewildered Alexander.

"Oh," said Alexander. "Could be."