[a_vanderbilt]

Greed. Those kinds of ads pay more. Interrupting the content means they can sell the spot as something people will actually see because they are forced to.

[sircastor]

More like desperation. The only real source of money online is ads sales. Nobody is making bank from putting ads on their site. They might be making enough for hosting.

Though I guess it could be described as greed on the part of the advertisers?

[RockRobotRock]

Yeah, it's greed. Greed by advertising networks, greed by the companies placing the ads, greed by the reader wanting unlimited content for free.

[a_vanderbilt]

This is the most correct response, and the only one which acknowledges the role of the reader.

[1vuio0pswjnm7]

"Greed."

I think that's right.