There are, of course, multiple responses to the fact that the first trailer for Marvel's Thor: Ragnarok shattered records in terms of viewership in its first 24 hours.
For example, it could be looked at as more evidence that trailers are, in general, getting more views more quickly these days: Stephen King's It had almost 200 million views in its first 24 hours, and Disney's Beauty and the Beast got 127.6 million in the same time period. Thor's 136 million fits into that trend comfortably (and sets up the question of just how popular the Star Wars: The Last Jedi trailer will be on its first day, whenever that is).
But what is it about Ragnarok that made it more popular than, say Captain America: Civil War, or Doctor Strange? Is it really just that people watch trailers more often these days, or is it something else? I suspect the latter is the case, and that the "something else" in question goes beyond the simple fact that the Ragnarok trailer was a particularly good trailer. The differentiator, and the reason so many people checked it out, I would argue, is because it played against expectations.
Sure, there was an audience hunger for Thor's return, given that he's been missing from the big screen since 2015's Avengers: Age of Ultron. (The Hulk, too; apparently Ragnarok is where the characters who skipped Civil War ended up. Here's hoping there's a Samuel L. Jackson Nick Fury cameo to cement this theory.) But along with that hunger, there was an idea of what a Thor film was, and who Thor was as a character; in both cases, the answer was a mix of sincerity and self-consciousness. The Thor movies have lacked the comedic zing of an Iron Man or Guardians of the Galaxy, or the dramatic scope of a Captain America: The Winter Soldier or Marvel's The Avengers. They're movies that appeal to fewer people, and even to those people, seem a little less exciting than their brethren.
Except Thor: Ragnarok seemed entirely different. The trailer is funny to a degree that only Guardians had managed before in terms of Marvel movies, and in a way that seems at once sillier and more self-aware. (The "He's a friend from work!" line, and Chris Hemsworth's delivery of it, is a joy that's simultaneously smarter and far dumber than anything James Gunn has brought to Marvel's cosmic heroes so far.) It's an ideal punchline to a trailer that started with a similarly aware joke - Thor essentially doing the record scratch "Yep, that's me, you're probably wondering how I got into this situation" meme for real - before demonstrating, over and over, that this wasn't the Thor movie anyone was expecting.
The moments that upset expectations are all throughout the trailer, from the obvious - Thor's hammer is destroyed! Thor gets a haircut! - to the more subtle, with a color palette and look that feels very much outside what's come before in this series, and character designs that look unlike anything that's come before, whether it's the warpaint look of Thor and Valkyrie or the Jack Kirby-esque design of Hela's headpiece. Add in Led Zeppelin on the soundtrack - another way in which this felt more influenced by Guardians of the Galaxy than the earlier Thor movies - and the trailer couldn't have announced that it was unlike what the audience was anticipating any more without retitling the movie Not The Thor Movie You Thought, Right?
That made it something that people wanted to watch again. Not just because it was good - and, again, I emphasize that the trailer was very good - but because, given the previous Thor movies and the character's appearances to date, the most immediate response to the trailer on first viewing was akin to, "What was that? I have to watch again, because that wasn't what I was expecting at all."
Whether this translates into a good movie isn't something we'll know until November, but - just in terms of prompting a new level of excitement for a property that might not have been the most well-loved Marvel series, and unleashing a wave of positive word of mouth for a project that some might have forgotten was coming - Thor: Ragnarok demonstrates ably the value of ignoring expectations in favor of following instincts and coming up with something unexpected. Would that more movies were so willing to surprise the audience.