I don’t think this has to do with age. There’s plenty of younger generation users on reddit. Reddit offers communities based on specific subjects. Social media, however, is based on networking with friends without a specific subject in mind, plain and simple.
You have to gauge if your intended audience is interested in discussing a specific subject (in detail), or simply to network with his or her friends and show off.
Tumblr, facebook and twitter, at the most, offer content curation which in turn allows more networking. That’s why things are based on custom post types and styling. It’s meant to be a visual cue for a user to understand without reading text that “this is an image post” or “this is a quote”. It’s meant for swift digestion because the content so much isn’t the focus. It’s the social networking between users and the relationships that form.
Did you originally want to use Discourse as a social media network? I honestly don’t know if that’s possible.
Furthermore, Discourse has plugins (Onebox, Lazy Youtube Loader) that help with things such as videos to be posed in-line a conversation. Discourse isn’t all about text, but the focus is discourse, which is conversation. Tumblr and all related are not meant for that in any shape or form. If your users want to learn more about video animation, then I would think they want to discuss how to be better and get feedback on their creations. Discourse works wonders for that. But not if your audience doesn’t want to discuss.
There are many software solutions that can be deployed to the cloud that allow someone to create their own social network. That might be more what you’re looking for.
Because I can tell you the online forum culture isn’t dead. It was held back by the crappy forum software it was usually hosted on that wasn’t hip with the times. Nowadays there’s trolls, spammers and unsavory folk who want to derail the conversation which Discourse helps with without intense manual/Human moderation. Reddit offers something to combat that (the points system) while also allowing specific-subject communities (reddits) to be created on the fly. Even though their threading system hurts my brain to focus and read, there was obviously a lot of people who saw the contrary and that’s why reddit has exploded in popularity.
Discourse is for discourse.
For that, I think it would be neat to have a small-thumbnail image gallery (and video gallery?) below the list of posted links in the OP’s meta info bar. In fact, that would be amazing, especially for media-intensive conversations, such as for art study (which is one area I am extremely focused on). EDIT2: This would help if each image didn’t post to the image itself, but instead jumped to the reply it was first posted into, for better context into why it was posted in the first place. If they need to see it bigger, they can click the image itself in that reply.