imbckagn - 3:29 am on Apr 29, 2010 (gmt 0)
Well I'm not a premium publisher but I do well with Adsense. Now that you mention it the other few websites I saw it on are high Adsense earners. Maybe it's something new they are trying for the "in between" average and premium?
I will keep an eye out and post back if I see it on what I would consider average website but either way I hope it sticks.