Andy Beaumont on the plague of Pop-Ups 2.0 and the reason why publishers of all sizes are rushing to put them on their sites (hint.. doing analytics wrong):
I have tested this design pattern with real people, and a significant portion of them believe that they must do what the box is begging them for in order to close the overlay. These people remember, they’re people, not “conversions”, are signing up to a newsletter they don’t want. They’re then going to be irritated by it for several months until they work out how to unsubscribe from it. The analytics guru you brought in is walking away with a chunk of your money, in exchange for having pissed off a whole bunch of existing and potential customers.