Watch out cable TV, YouTube is coming to get you. And now it's after your paying subscribers in Boston, Tampa, Seattle and 11 other cities.

YouTube TV, Google's live TV streaming service that costs $35 per month, is available in 14 more US cities starting Thursday. Combined with the 15 cities already served, half of the households in America can now subscribe to YouTube TV.

The service also adds national news network Newsy and the Tennis Channel to its slate of 50-odd live channels today, as well as Boston's NESN, home of Red Sox baseball. Coming soon are My TV and CW networks in select markets. (The CW network is a joint venture of CBS, the owner of CNET, and Warner Bros.)

But Google's expanding venture into pay TV won't stop there. In "the coming weeks" YouTube TV says it will add 17 more markets including Denver, Cleveland and St. Louis, bringing its total to 46 markets and 64 percent of US households. See below for a full list of the new cities.

Not to be confused with the free YouTube you know from countless how-to, music and cat-related videos, YouTube TV is one of a growing number of options aimed at cord cutters and "cord nevers" seeking an alternative to traditional cable TV.

Like competitors DirecTV Now, Hulu with Live TV, PlayStation Vue and Sling TV, it streams live and on-demand TV over the internet to TVs, phones and computers, with no contracts. These services range in price from $20 to $40 per month and offer some combination of national channels (ESPN, Bravo, FX, MSNBC) as well as local (ABC, CBS, Fox, NBC).

Now playing: Watch this: YouTube TV now covers half of the United States

A locals-first strategy aimed at millennials

The biggest difference between those other four live TV streaming services and YouTube TV is a focus on local channels. Like the others it has a solid if not comprehensive array of national networks such as ESPN and FX, but unlike its competitors, YouTube TV is not available nationwide. Unless you live in one of those 29 (soon to be 46) markets, you can't subscribe to the service.

If you're used to internet video being available everywhere, that can seem like a pretty big problem. But for YouTube TV it's a strategy. I asked Kelly Merryman, managing director of content partnerships at YouTube, about its unique approach.

"We want to make sure we have at least three of the four broadcasters live on a local basis, getting those affiliate deals done so we could provide great local coverage. We're really focused on the top 50 DMAs and lighting those up," she says, referring to Direct Market Areas, as measured by Nielsen.

Sarah Tew/CNET

In other words, YouTube TV will only launch in cities where it can offer three or four local broadcasters -- ABC, CBS, Fox and/or NBC. Nineteen of its 29 markets have all four, with the other 10 missing just one. People in Dallas can't get their local ABC station on YouTube TV, for example, and Seattle subscribers miss out on Fox (bummer, Seahawks fans). Check out my updated local channel chart for details.

There's a big difference between local and national channels. Nationwide channels like AMC, TNT and The Disney Channel offer one or two national feeds (a second one is sometimes time-shifted for west coast viewing), but local stations typically air news and other programming endemic to the area, in addition to programs from the big four networks. Because most local stations, aka network affiliates, are owned by companies other than one of the big four networks in question, they usually require separate contracts with providers such as streaming services, cable systems and satellite networks.

YouTube TV's locals-first approach means users won't have to worry about missing one of those networks. Or at least, more than one of them.

"When we first launched this service we spent a lot of time with our users trying to understand what they were seeking," says Merryman. "What we heard is that they were seeking a service that leaned into both local and live. We wanted to prove that that was what was missing, and what was necessary to reach this millennial audience."

And Merryman says it's working so far. The majority of YouTube TV subscribers are millennials, and the majority of content subscribers watch on the service is live, as opposed to on-demand or recorded on the cloud DVR, she says. YouTube declined to provide specific numbers, however, and also wouldn't say how many subscribers it had or how many hours per day people watched.

The battle to stream the big four networks

All five live TV streaming services continue to add local channels, and signing them up has become an arms race. According to my running tally, with this expansion, YouTube now has more total local channels (105) than DirecTV Now, although it still trails Hulu and PlayStation Vue. Its impending 17-city expansion would vault it into first place if Hulu and Vue stand still, but that's not happening.

Hulu, the last of the five to launch, is now in the lead with 200 local channels as of today, 119 of which are CBS stations. PS Vue's latest local channel expansion of 11 ABC and four NBC local stations brings its total to 186 by my count. DirecTV Now recently announced the impending addition of 14 CBS stations, filling the biggest hole in its lineup, and plans to have 170 by this fall. Even laggard Sling TV recently added a local channel, NBC in Boston.

YouTube TV's local channel advantage over the others shows up best in cities such as Baltimore, Minneapolis and San Antonio, where it's the only one to offer all four locals. In many such places its competitors have two or three, at best.

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Signing up Sinclair

One of the biggest reasons YouTube TV is able to expand local coverage is a new partnership with Sinclair Broadcast Group, the nation's largest owner of local broadcast stations, which was also announced Thursday.

"We believe that our viewers want the ability to access content on any screen and having this relationship with YouTube will provide value to not only our viewers, but our advertising relationships as well," said Barry Faber, Sinclair's executive vice president for distribution and network relations in a statement. "We appreciate that Google, the owner of YouTube TV, recognized the importance of carrying all of the local broadcast affiliates to their effort to attract subscribers to this new service."

The agreement says that all of Sinclair's ABC, CBS, Fox and NBC affiliates will appear on YouTube TV as that service launches in a market. Sinclair also owns the Tennis Channel, and its My TV and CW affiliates will appear on YouTube TV soon, along with Comet TV.

Sinclair has also made deals with other streaming providers, but not to the same extent as YouTube TV. A Sinclair representative told CNET that currently Fox and CBS affiliates are available on PlayStation Vue, and ABC stations are available on DirecTV Now, but no Sinclair stations are available on either Hulu or Sling TV.

Indeed, Sinclair is set to get even bigger: It owns more than 170 local channels and is currently buying Tribune Media, which owns 39 more. But that increasingly large national footprint is not without controversy. HBO's John Oliver dedicated the bulk of his July 2 episode to detailing the company's drive to make its local newscasts more friendly to conservative causes, while a more recent New York Times report documented what it called the company's "increasingly tight relationship with the FCC" -- the arm of the Trump administration responsible for approving the Tribune deal.

Sinclair and YouTube declined to comment about those reports for this article.

Sarah Tew/CNET

What's next for YouTube? Big-screen apps

YouTube TV's accent on local TV could pay off, but according to Merryman its next focus after expanding to more cities will be on improving how people actually use the service.

"What we're hearing is that it's a great UI, that they love the variety of programming, but they really are seeking a better living room experience," she said. "So that has been an area that we've really focused on."

Right now YouTube TV is very phone-centric. It has Android and iOS apps for phones and tablets, and can also stream to computers, but the only way to watch on an actual big-screen TV is with a Google Chromecast or AirPlay via an Apple TV, both of which require you to use your phone as the remote control. By comparison, all of YouTube TV's competitors have real, big-screen apps on TV-connected platforms and devices like game consoles, Roku, Amazon Fire TV, Apple TV and Android TV.

When I asked about those platforms Merryman didn't confirm any specifics, beyond saying "this fall we'll be rolling out a number of different living room solutions." Stay tuned.

YouTube TV's aggressive expansion provides yet another alternative for millions more Americans who want to watch their shows but don't want to subscribe to cable. With its accent on local channels and other cool features like an unlimited cloud DVR, it's an increasingly strong player in the next generation of television.

The 14 new markets that get YouTube TV today:

Baltimore



Boston



Cincinnati



Columbus, Ohio



Jacksonville-Brunswick



Las Vegas



Louisville



Memphis



Nashville



Pittsburgh



San Antonio



Seattle-Tacoma



Tampa-St. Petersburg-Sarasota



West Palm Beach-Ft. Pierce



The 17 additional markets available in "the coming weeks":

Austin



Birmingham



Cleveland-Akron



Denver



Grand Rapids-Kalamazoo-Battle Creek



Greensboro-High Point-Winston Salem



Harrisburg-Lancaster-Lebanon-York



Hartford-New Haven



Indianapolis



Kansas City



Milwaukee



Norfolk-Portsmouth-Newport News



Oklahoma City



Raleigh-Durham



Salt Lake City



San Diego



St. Louis



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