The lucky fans who were in attendance at D23 and San Diego Comic Con this past month (more power to you if you were at both) were given the very special treat of an Avengers: Infinity War trailer. It sounded seriously epic and people at home waited anxiously for Marvel to release the trailer online. However, Marvel opted not to do that, with the rest of the world having to rely on second-hand accounts of the footage. While that understandably stinks for all of us left in the dark, it's still a smart move on Marvel's part and it's actually a good thing that they haven't put the trailer online.
Everything about a trailer, from the shots used to the time it is released to the public, is carefully calculated. People who went to school for marketing sit down at a table (a really nice one, I bet) and plan out the absolute most effective spot so that the trailer gets a great reaction. Even if the trailer itself kind of sucks, there's a reason it's dropping when it is. In the case of Avengers: Infinity War, the powers that be seem to have felt that it was too soon to release the trailer to the public. The movie is still a little less than a year away, and it may be too soon to drum up such intense hype with such a long way still to go.
But what about D23 or Comic Con? Those people all got to see it! Well, you have to consider the specific environment of a convention. Releasing a trailer at a Con is a great way to raise awareness/excitement, and that's a really easy thing to do. Everyone there is super pumped to see whatever it is they're there to see. The energy of the room is electric and I'd bet that even if something were bad, people would still lose their minds when they got to see a new trailer because everyone is just so happy to be there and experience it. Reactions out of D23 and San Diego Comic-Con prove this point. So, when Marvel shows the first-ever trailer for Infinity War -- a movie already hyped into oblivion -- people are going to react big time. Then those people go on social media and build more hype so that when a trailer finally does arrive online, people are likely to click that link fast.
One also has to remember that these exclusive Con trailers are made to be exclusive for a reason. James Gunn has said that he and Marvel don't like to release footage premiered at Comic-Con because it doesn't hold up under repeat viewings. In some cases, the visual effects work is still early and unfinished. There's a difference between showing a crowd of excited fans unfinished footage one time than millions of people worldwide dissecting it on repeat. No one has really talked about how the Infinity War footage actually looked, but it's not like people can go back and check. All they remember is Thanos throwing planets around. When Marvel does release a trailer for Infinity War, it will be: A) finished, and; B) likely contain some new footage that no one has seen yet. That sounds a lot better than something that was made for a one-time limited audience.
While plenty of studios release their promotional materials at the same time they debut at Comic-Con (Hello, DC), Marvel is something of an exception. They typically don't release most of their footage from the panels unless it's ready for a mass audience (See: the awesome Thor: Ragnarok trailer). They do this, in part, because something at Comic-Con needs to be just for the people at Comic-Con. It's a reward for buying tickets, waiting hours in line, and wading through huge crowds of people. If you had to sit in a line for almost an entire day, only for everything you waited to see immediately released online, you'd probably be a little pissed. At least Marvel is helping make that experience worthwhile by showing slick Black Panther footage or a trailer that had already built up buzz from the previous week.
True, the Avengers: Infinity War trailer has already leaked online, so you'd figure that Marvel should just release it now that the cat's out the bag. Our own Mike Reyes argues that it should be released right now. Read his take on the matter. But, again, that footage is likely not as good as what they are assembling for the REAL trailer that'll be slapped in front of every movie from November (I'm guessing; that's when Ragnarok drops) to May. The description of what fans have seen from the movie thus far sounds incredible, but that just means that it'll be worth the wait when Marvel deems to finally take pity on all of us poor souls.