UK spy agency collected sexually explicit images from Yahoo Messenger

Like the NSA's collection of millions of innocent people's phone, email, and credit card data, the webcam surveillance program was carried out in bulk, creating a massive database where the communications of hundreds of thousands of people could later be scanned by analysts for clues or patterns.

However, unlike the phone database, OPTIC NERVE also automatically downloaded the content of video communications - taking a screenshot from the video feed every five minutes, the Guardian said.

One snippet of a leaked document published to the Guardian's website appears to show that GCHQ hoped to eventually "collect images at a faster rate," or perhaps even download all the webcam videos in their entirety.

Even at one screenshot every five minutes, material published to the Guardian's website appeared to show UK analysts being deluged with X-rated footage.

"It would appear that a surprising number of people use webcam conversations to show intimate parts of their body to the other person," another snippet of an intelligence document published said. It went on to say that an informal study had found that between 3 and 11 percent of all the images carried "undesirable nudity."