"It's in everyone's best interest in the online community to find and stamp out click fraud," Pellman said. "The fraudsters are trying to stay a step ahead of those efforts."
Recognizing at least that everyone needs to play a part, it's no good blaming just MS or Google or Yahoo for the wrongs of the web.
Perhaps hosting sites could do something about malware laden sites on their servers, perhaps on an educational level, people could be made aware that maintaining a level of "cleanliness" on their own computers would alleviate part of the problem, as for ISP's, already able to block P2P/Torrent traffic, could enabling a filter on traffic to/from malware laden sites.(This I already know is feasable, and for instance, is used for blocking child porn sites).
Don't go shooting me down for offering an opinion that may vary from your's, it's my right, exactly the same one you're using to respond.