In my modest opinion, it's due to the fact most PTCs don't run a serious object. Most of them promote questionable sites as gambling ones. In the worst cases, there is even the presence of adult ads, to worsen things. Users are not required to rack their brains to improve the quality of the site's services. It's only tons of click and tons of surf in change of crumbs. Sorry, but I'm not able to see where is the helpfulness of lot of PTCs and when a business lacks whatever helpfulness, whatever usefulness, it simply fails. If it happens a useful activity gets broken too, how much more a PTC