[notdanariely]

My other comment in this thread addressed this, but basically, I think it's a filter for removing those site visitors unlikely to become customers, allowing a company to focus on people who are receptive to the medium (popup) as well as the message. These people are going to be easier to advertise to, because they don't get pissed off when you put an ad in front of them.

The software analogy is invalid, because those people are already your users or customers. In the case of reading the article, think of a popup as a criterion filter in much the same way as 419 scammers use poor english.