Content owners NBCUniversal and AMC continue to respond to shifts in viewer behavior with two new and telling Internet-delivered subscription services. But their approaches to these shifts represent two very different understandings of the future of TV. NBC is diving headfirst into niche subscription sports channels, while AMC is offering an ad-free version of its linear TV channel to stream. AMC has already launched two niche OTT services: the horror movie service Shudder and the indie movie service Sundance Now. But AMC CEO Josh Sapan has been reluctant to take the flagship AMC channel outside the pay TV ecosystem. Responding to consumers’ sudden and vocal aversion to advertising – and desperate to compete with the likes of Netflix and Amazon…