Aereo's technical and business plan is very simple. The company uses arrays of thousands of tiny antennas to receive OTA TV channels. A subscriber in one of their covered cities, which currently include Atlanta, Austin, Baltimore, Boston, Cincinnati, Dallas, Detroit, Houston, Miami, New York and San Antonio, is then assigned an individual antenna from that array and its signal is send to them over the Internet. There, customers can use a variety of devices and apps, such as Google Chromecast, Apple TV, Roku, most major Web browsers, and apps on Android and iOS devices to watch their local OTA broadcasts.
Since then the court cases have come rapidly. Sometimes Aereo has won and sometimes they've lost. Starting on April 22nd, the Supreme Court of the United States (SCOTUS) will decide once and for all if Aereo can pursue their existing business plan or if they'll go out of business. It seems unlikely that the broadcasters would allow the upstart Aereo another extension of the existing commercial television business.
If Aereo were to win, it would empower the cord-cutter movement of people who want to cut the cable cord in favor of using the Internet for all their television watching needs. This tends to be much cheaper than using cable or satellite for television.
Legally, according to the SCOTUS Blog, "The Supreme Court [had] held the view that if an enterprising firm came along that made it easier for television viewers or radio listeners to get the programs they wanted, if they paid a fee, free over-the-air programs were fair game: royalties to the broadcasters didn’t have to be paid even though their programs were copyrighted." Congress, on the other hand, has waffled on the issue.
The legal arguments will revolve around the meaning in the "broadcast world of two words (and variations thereon): 'perform' (or 'performance') and 'public' (or 'publicly')." Aereo claims that all they're doing is following in the legal footsteps of Betamax and the DVR by enabling customers a choice on how to deal with public broadcasts. In both examples, the courts rule that the customer is king and that they could choose whether to watch a broadcast live or save it for another time.
The broadcasters disagree. Gordon Smith, the president of the National Association of Broadcasters, said, "Quite simply, Aereo takes copyrighted material, profits from it, and does so without compensating copyright holders." The media companies will argue that Aereo is making their OTA signals "public: and thus must pay their fees." Aereo will maintain that their retransmission of the signal are sent from private antenna to private individuals for their personal use.
Who will win? There's no telling at this point. I expect SCOTUS to focus very narrowly on Aereo's specific implementation of OTA to the Internet rebroadcasting. They don't want to get in the way of future technical advances. But whether they'll buy Aereo's arguments is entirely up in the air.