Are these types of sites against the ToS? I wouldn't think so. I'm thinking that if the Adsense ad reloaded each time they clicked on a new image, it could add up to a lot of pageviews.
I guess it is ok as long as there is no nudity shown on the site. You might want to ask Google to be sure.
It's ok, as long as you don't ask users to reload the webpage, and actually the impressions will drive down your CTR and you'll earn less. These type of sites aren't easy to monitize.
Yes, CTR shows Google how many clicks you get per impressions, of course they would pay more to people with higher CTR then lower, this is why they have smart pricing, they pay less to low CTR to help advertisers get a higher ROI.
The hot or not sites are long gone...I dont think many people check out those...I remember when they were popular
There's one that is for dogs and another for cats that seems to be pretty popular. I figure there's always going to be people that never knew about a concept from the past and would find it cool or fun. I like the concept, even if it is old. I still may not do it though.