Hmm..question is how this is gonna work and if its gonna work. 
Most of us don't want to pay no attention to ads and probably wont even if we get paid a buck for it.
And how do they actually measure user attention? 
Is it if the user don't click away? If so, you can just leave the ad on and do something else with you attention, intentionally not taking in the message.
"The Attention Value for the ad will be calculated based on incremental duration and pixels in view in proportion to relevant content, prior to any direct engagement with the ad. "
Very fluffy and doesnt really say much..