Warning: This article contains spoilers!

Disney's Agents of SHIELD competes with CBS' NCIS

Tweeting away during the midseason finale, Agents of S.H.I.E.L.D. stars Brett Dalton, Ming-Na Wen, and Clark Gregg, Image source: Disney/Marvel

Get ready, Marvel fans, because your favorite show is set to return with an all-new episode this Tuesday.

Of course, I'm referring to Disney (NYSE:DIS) Marvel's Agents of S.H.I.E.L.D., which shocked fans early last month by ending its midseason finale with the kidnapping of Agent Coulson.

But keep in mind you're not the only ones who can't wait for a new episode of Agents of S.H.I.E.L.D. to arrive. The folks over at Disney's ABC must be getting antsy by now, especially considering S.H.I.E.L.D. currently stands tall as the network's highest-rated program in Tuesday's 8 p.m. hour in four years.

So how, exactly, is Agents of S.H.I.E.L.D. performing so well? Here are three reasons:

1. DVR is king

But wait, you say, haven't all the headlines panned Agents of S.H.I.E.L.D. for its falling ratings? Well, yes they have...but most headlines don't tell the whole story, either.

For example, a quick web search for "Agents of S.H.I.E.L.D. ratings" currently yields several articles lamenting the fact its midseason finale "only" garnered 6.11 million viewers, resulting in a series-low 2.1 rating for adults 18-49. And that's true ... even though it ignores the fact S.H.I.E.L.D. had just gone 10 consecutive episodes at number one with the coveted men's 18-34 demographic.

However, to give credit where it's due, CBS(NYSE:CBS) perennial favorite in NCIS did win the night once again, earning a solid 2.9 rating with an incredible 19.3 million viewers.

But in today's technology-driven world, those live ratings aren't all they're cracked up to be anymore. Thanks largely to the ever-growing adoption of digital video recorders, many people are increasingly watching television shows on their own schedule.

As it turns out, based on the Live + 7 day numbers as driven by DVR playback, Agents of S.H.I.E.L.D. has earned a mammoth 4.8 rating in adults 18-49, making it Tuesday's undisputed number one show this season to date. Meanwhile, NBC's The Voice currently stands in second place with a 4.6, and CBS' NCIS remains a distant third at 4.2.

2. Bringing the thunder

Next, Agents of S.H.I.E.L.D. remains happily guilty by association with its hugely popular Marvel box office counterparts.

By operating in the same universe of characters, Disney was able to take advantage of this novelty in November with a movie crossover following the release of Thor: The Dark World. Unsurprisingly, renewed public interest in the show enabled the show to successfully reverse its seven-week live ratings downtrend -- and yes, also likely steered droves of curious new fans to watch later on their DVRs.

As a result, I wouldn't be too surprised to see yet another crossover centering around Captain America: The Winter Soldier in April. Then it can happen again with Guardians of the Galaxy later this year. And again with Avengers: Age of Ultron in May 2015. And yet again with Ant Man after that...

Wash, rinse, repeat, and Disney's left with a Marvel-ous long-term formula for periodically gathering new viewers.

3. Embracing social media

Finally, it's no mystery the folks at Disney and Marvel have social media sites like Facebook and Twitter pretty well figured out, but I'm especially impressed by the extent to which Agents of S.H.I.E.L.D.'s cast utilizes the new communication mediums to reach out to fans.

In fact, ABC even held what they called a "Tweetapalooza" leading up to the show's most recent episode, encouraging viewers to keep an eye not only on the official Agents of S.H.I.E.L.D. Twitter account, but also the verified accounts of each of the show's stars.

And though that hour resulted in some particularly entertaining exchanges, the cast hasn't stopped there. You can still find each of them regularly interacting with the general Twittersphere every day -- and undoubtedly boosting the show's wide appeal in the process.

Fool contributor Steve Symington has no position in any stocks mentioned. The Motley Fool recommends Facebook, Twitter, and Walt Disney. The Motley Fool owns shares of Facebook and Walt Disney. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.