Welcome to WebmasterWorld Guest from 188.8.131.52
Sites that are displaying your ad code which are not included in your authorized sites list. Clicks and impressions from these sites will appear in your reports, but you will not generate earnings from them.
If someone took your content and also scalped your ads, let it run!
Free earning for you "well not free, they are using your content, so you deserve to be paid".
Just ignore it.