It's been a long time coming, but it looks like television, the reigning champ of home entertainment for generations, may finally be displaced by our smaller, more portable digital devices. A new study suggests the dethroning should occur this year.

According to tracking firm eMarketer's data, in 2013 adults in the U.S. will spend 5 hours and 9 minutes every day on average using digital media in some form — be it apps, streaming video, games, or browsing the Web. They will also, meanwhile, engage on average with 4 hours and 31 minutes of TV.

It's second (and third) screens that contributed to digital's growth, the company says. Although time spent on desktops and laptops dropped slightly, people spent about an hour more on average doing non-voice things on their mobiles.

It makes sense: mobile phones are our constant companions, and every minute spent checking your Instagram feed, chatting on Facebook, or watching YouTube is one less you could be watching TV. And how many times during a boring show have you checked Twitter or played a quick level of "Cut the Rope"?

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Of course, it's not a simple thing to collect or even define some of these figures, so eMarketer was careful to point out that other research companies reached different conclusions. For instance, it estimated that among all consumers, about 2 hours and 19 minutes of a person's media consumption time was online. But a Temkin Group study they cite puts the figure at 5 hours and 48 minutes. So take all these figures with a grain of salt.

That said, the trends shown are unmistakeable: People are watching the same amount of TV or slightly less, while their use of mobiles and online services is skyrocketing. Even if eMarketer's estimate that digital will overtake TV is premature, it's sure to happen soon — or maybe it happened already.

Devin Coldewey is a contributing writer for NBC News Digital. His personal website is coldewey.cc.