7 0 s ▁and ▁initially ▁grew ▁in ▁popular ity ▁as ▁it ▁allowed ▁subscri bers ▁to ▁watch ▁mov ies ▁without ▁time ▁or ▁content ▁editing ▁common ▁with ▁over - the - air ▁television ▁broadcast s ▁of ▁the atr ically ▁released ▁feature ▁films ▁and ▁without ▁inter ru ptions ▁by ▁advert ising . ▁While ▁H BO ▁continues ▁to ▁feature ▁the atr ical ▁films ▁and ▁spe ci als , ▁the ▁service ▁eventually ▁became ▁one ▁of ▁the ▁first ▁cable ▁channels ▁to ▁successfully ▁vent ure ▁into ▁original ▁programming ; ▁by ▁the ▁late ▁ 1 9 9 0 s , ▁H BO ▁began ▁to ▁be ▁known ▁for ▁ground bre aking ▁first - run ▁series ▁( such ▁as ▁The ▁Larry ▁Sand ers ▁Show , ▁The ▁S op ran os ▁and ▁Sex ▁and ▁the ▁City ) ▁that ▁were ▁ed g ier ▁and ▁more ▁ris que ▁in ▁content ▁than ▁those ▁allowed ▁to ▁air ▁on ▁broadcast ▁networks . ▁Other ▁pay - extra ▁networks ▁launched ▁in ▁the ▁years ▁subsequent ▁to ▁H BO ' s ▁launch ▁including ▁Show time , ▁which ▁launched ▁on ▁September ▁ 1 6 , ▁ 1 9 7 6 ▁with ▁a ▁similar ▁format ; ▁and ▁movie - orient ed ▁services ▁such ▁as ▁Star ▁Channel ▁( which ▁launched ▁in ▁April ▁ 1 9 7 3 , ▁and ▁later ▁became ▁The ▁Movie ▁Channel ▁in ▁November ▁ 1 9 7 9 ) ▁and ▁H BO - owned ▁Cin em ax ▁( which ▁launched ▁on ▁August ▁ 1 , ▁ 1 9 8 0 , ▁and ▁later ▁became ▁more ▁known ▁for ▁its ▁late - night ▁soft core