It comes to my attention that my ads were displayed on some website hosted on those free hosting server. Those sites appear to be pretty good and have good contents on them. Does google allow that?
Google's TOS does not specify where a site can or can't be hosted https://www.google.com/adsense/policies
should it matter if the site is hosted on free hosting or paid hosting? if the visitors are genuine, why not?
it shouldnt matter as there are alot of sites on free hosting services that are a great value to the online community. like daboss said as long as the visitors are real, why not?