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VLK spoke about script blocking etc. I myself install avast in my relatives PCs and I recently got a big thanks because of avast!. avast! indeed blocked a Facebook link that tried to exploit something and install ZerkAccess rootkit. The link was blocked in it’s roots as soon as it was clicked on. That’s the true protection avast! offers 
The same link, in the other hand, was opened in PC that had no protection at all. It was hard to remove the Rootkit because it made things very hard inside windows ^^