Working at an IPTV-operator myself I don't see why you should limit yourself to porn. Sure, porn sells, but there is no reason why you can't offer full TV service through an IP multicast network, which my employer in fact does. 

Naturally, we have a VOD (Video On Demand) service as well, including the obligatory naughty flicks. But being able to rent a movie just by grabbing the remote is all good for regular films as well.

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Max Romantschuk