Aereo's service starts at $8 a month and is available in New York, Boston, Houston and Atlanta, among 11 metropolitan areas. Subscribers get about two dozen local over-the-air stations, plus the Bloomberg TV financial channel.
In each market, Aereo has a data center with thousands of dime-size antennas. When a subscriber wants to watch a show live or record it, the company temporarily assigns the customer an antenna and transmits the program over the Internet to the subscriber's laptop, tablet, smartphone or even a big-screen TV with a Roku or Apple TV streaming device.
The antenna is only used by one subscriber at a time, and Aereo says that's much like the situation at home, where a viewer uses a personal antenna to watch over-the-air broadcasts for free.
Chief Justice Roberts repeatedly asked Frederick whether the tiny antennas existed for any reason other than to avoid paying the broadcasters for their content. "Is there any reason you need 10,000 of them?" Roberts said at one point. He suggested that it might not affect his view of the case if there was no other reason.
But Frederick said it was much cheaper for Aereo, backed by billionaire Barry Diller, to add equipment as it grows, rather than start with a single large antenna.
Broadcasters including ABC, CBS, Fox, NBC and PBS sued Aereo for copyright infringement, saying Aereo should pay for redistributing the programming the same way cable and satellite systems must or risk high-profile blackouts of channels that anger their subscribers. Some networks have said they will consider abandoning free over-the-air broadcasting if they lose at the Supreme Court.
The broadcasters and their backers argue that Aereo's competitive advantage lies not in its product, but in avoiding paying for it.