I just noticed it this morning. I usually notice when the popup blocker blocks something so I'm inclined to believe it's fairly new.
Some of the more interesting questions are:
Assuming your travel dates are flexible, what is the minimum price difference that would cause you to change your travel dates?
(Select one)
$25
$50
$75
$100
$200 or more
Not interested
Assuming your airport of destination would be flexible, what is the minimum price difference that would cause you to change your airport of destination?
(same list)