Ask HN: What are the innovations in the world of Web Porn?

When I first used internet in 1997, www was very much different than what it is now. Ordinary man like me need not waste words explaining how the web has evolved. However some trends are common. In those days websites provided content and as users we just consumed it. Today we talk of collaboration, social nature of web sites where everyone is contributor and consumer. But has there been any research, survey in the world of web porn? Has that industry changed in some way? OR is it same thumbnail based galleries? arent they innovating ? Arent they investing in developing technical competence of innovation ? Can someone just suggest any good quality write up on this topic ?