Aereo Delivers Great Local TV Service to Cord-Cutters. For Now.

You thought that language was getting complicated when Bill Clinton said, “It depends upon what the meaning of the word ‘is’ is.”

Now a great national legal debate is going to hinge on what the definition of broadcast is.

But first, some background.

Aereo is an $8-a-month service that lets you tune in to TV channels that are broadcast over the air, from the comfort of your own laptop or tablet. We’re talking about the channels that ordinarily require an antenna to receive. Or you can record them, using something like a TiVo that’s installed at Aereo headquarters on your behalf.

Who needs TV this way?At least a million people a year are “cutting the cord” — canceling their cable TV or satellite service. They get their TV fix by watching shows supplied by Netflix, Hulu, and Amazon. And they save a ton of money. (Here’s our Yahoo Tech guide to cutting the cord.)

If you think about it, the shows you can get from Aereo are exactly the ones that cord-cutters can’t get on their computing devices any other way: local news, sports, talk shows, sitcoms. Aereo is ingenious, really, and it is essential for a lot of cord-cutters. iPads don’t have antenna inputs.

Using Aereo is simplicity itself. You can find shows by scrolling through a channel grid. It’s manageable, since it’s only 35 channels.

Or you can use Aereo’s very smart search box. You can search for shows’ names, of course. But you can also type keywords, genres, dates, or networks. Or combo phrases like “on NBC tomorrow night,” or “comedy on CBS.”

Anything that’s being broadcast right now, you can watch live (actually, delayed about 6 seconds from real time). The quality is surprisingly good, if you have a fast Internet connection. As with any online video service, the picture grows pixelated and blotchy as your Internet connection deteriorates.

Your TV can’t do thisBut Aereo is also a TiVo in the sky — a digital video recorder. Anything you see or find, you can also record. In fact, you get two “tuners,” so you can record two shows at once.

This recording feature, too, is as idiotproof as it gets. You can specify “New episodes only,” adjust the start or stop time, indicate how many episodes you want to save, and so on. (You can keep up to 20 hours of recordings on the $8-a-month plan. Or 60 hours for $12 a month.)

The channel assortment includes the big boys — ABC, CBS, NBC, PBS, and FOX, plus CW, Telemundo, and a bunch of lesser-known channels like Qubo, Live Well, ION Life, and Cozi.

You can watch your live or recorded shows on your computer, iPhone or iPad, Android phone, or tablet. If you have a Roku box connected to your TV, you can watch your Aereo shows on the big screen, too. Or, if you have an Apple TV, you can beam your Aereo shows to your TV from your iPhone, iPad, or Mac.

It all works incredibly well. It’s a joy to use, and everything works exactly the way you’d hope. There are, however, some footnotes.

First, Aereo is available in only 11 cities: New York, Boston, Baltimore, Miami, Detroit, Cincinnati, Atlanta, Houston, Dallas, San Antonio, and Austin. (16 more cities are slated to come online soon; you can see the list here.)

Second, you can watch your Aereo shows only when you’re in your home city. In other words, don’t think you can relax in your San Francisco hotel room, watching free recordings that you set up when you were home in New York. (The Aereo, in other words, is not aSlingbox.)

See Aereo fight for its lifeThird — and here’s the big one — the TV networks themselves are not exactly Aereo fans. In fact, they want to crush it like a bug. Watch:Katie Couric Interviews the CEO of Aereo

As they see it, Aereo is basically capturing the networks’ broadcasts for free and then collecting money from us to watch them. Aereo isn’t paying licensing fees for those shows, the way a cable company must.

Aereo disagrees. Aereo says that it’s simply an antenna-renting service. And indeed, it does maintain a separate tiny TV antenna for every single subscriber.

Each of these Aereo antennas is the size of a dime. Each Aereo customer gets one.

Now, Aereo has won a number of small legal battles so far, but the big one starts next week: The Supreme Court is set to hear the case. And the Department of Justice has filed a brief that expresses its opposition to what Aereo is doing, saying that it infringes on the broadcasters’ copyrights. That’s not a good sign.

The lawsuit may boil down to the definition of a broadcast. The Department of Justice believes that Aereo “transmits the same underlying performances to numerous subscribers” and is thereforebroadcasting it, illegally. Aereo argues that it’s not really broadcasting anything, since each subscriber gets an individual video stream of his own personal selections, on demand, independent of any other subscriber.

All of this reminds me of a very similar recent legal battle. In 2011, I reviewed a remarkable streaming-movie service called Zediva.com. It allowed you to watch any of the 100 most popular movies over the Internet, starting on the day they came out on DVD. No waiting for months, as you must on iTunes and similar services. And you got full access to director’s commentary, DVD extras, alternate languages, and so on. All for $2 a movie.

How did it do it?

It built a data center stacked to the ceiling with DVD players. Each was preloaded with one of those popular movies. When you, the customer, selected a movie to play, that DVD player actually sent you the video stream, across the Internet. You could control it from your house.

The movie companies were livid. “You can’t sidestep our restrictions and our availability dates!” they said.

But Zediva’s lawyers argued that it wasn’t a movie-streaming service — it was a DVD player-renting service.

Sound familiar?

Anyway, things didn’t end well for Zediva. The judge sided with the movie companies, and Zediva shut down its operations. It’s gone to the great CompUSA in the sky.

Aereo, as a product, is well done and economical. But, even so, it’s probably interesting to a fairly small number of people. Cord-cutters. Who live in select cities. Who miss the elements of live network broadcasts that they can’t get from Hulu or Netflix.

The legal story, though, is far more important. Both sides claim that the Supreme Court’s decision will have immense repercussions, affecting cloud computing, streaming video, TV-show availability, and so on.

As they used to say in the TV biz: Stay tuned.