As a writer, I will agree that something needs to be done about this. I was gutted the first time I saw an article of mine copy-pasted on a dozen blogs. Now that it happens every week, I've gotten used to it. The most irritating part is that often when looking for an old article I've done, the scrape sites come up higher on google than my actual article.
However, getting the advertisers to hand over a portion of the revenue could do more harm than good by legitimising the process of webscraping (which is, as someone above put it, a way to get "money for nothing"). Even if they hand over all the revenue, there will always be alternate advertisers for them to switch to. I wouldn't like to see my articles reprinted elsewhere with porn ads and flashing "YOU HAVE WON" scams slapped all over it.