The nominations for the Emmy Awards will be announced on Thursday in Los Angeles, and it is widely expected that, for the first time, the headlines will be all about Netflix.

Two programs created for that Internet streaming service, the drama “House of Cards” and the comedy “Arrested Development,” are leading contenders for best actor or best program nominations that formerly were the province of shows produced for broadcast and cable networks. And if they are nominated, it would be the first time that slots in the most avidly pursued categories went to programs not specifically produced for the medium of television.

The reaction to this development inside the traditional television business has been largely muted, with many executives suggesting that only the quality of the work is important. But to some, this is a moment reminiscent of the days when cable channels like HBO first began to challenge the dominance of broadcast networks like ABC.