There is a small bug with hta files. Ie users could easly say yes to this file... Then users homepage will be yours.
I accidently found one website , results are amazing this guy did it crazy, he had 300k hits daily and for 3 years this website got some high traffic.
You hijacking homepage must be only special search engin by google adsense,users should think this is something like google.
I guess this guy maybe earned 1000$ daily.
Its strange that adsense didn't kicked him for 3 years..