You mean just as a platform for people to sell videos they've made to youtubers?
Not being sure what you made, I can still say this however:
1. Did you solve a real problem that exists?
2. Having a free service doesn't mean you can't pay for advertising, it just means you'll take a loss on it. And it may very well be a good idea to PM some people with successful youtubers and ask what they think. Introduce yourself politely, and get some opinions (I'm still kind of unclear on what your site does)
3. You should have some sort of money plan. If you grow, your costs are probably also going to grow, at least have something in place to offset that.
4.Post the site on places like HN, Reddit (in the appropriate subreddits), and see what people think
Especially the people who are looking to add more value to their channels...You should definitely reach out (with a polite, well-worded email) to 1 or 2 high traffic users (I really mean send to a bunch, and maybe some small amount will respond/have feedback for you) - and push your product as a "extended content distribution platform" -- also, make sure it has a good name, maybe one that makes it really clear what it does.
Then, ask them if they're interested -- they can put links to their "spaces" in their videos/profiles, assuming they have extra content to share.
I think your idea is a little different, because you don't need to pitch to other devs, and you don't need to pitch to VCs, but instead you need to pitch to successful/unsuccessful youtube users. Also, don't stop with youtube, offer some Vimeo integration -- alot of early adopters, and generally open-minded people (I'd like to think) post videos there, and even relatively serious ones.
To be honest, I think you should even open this up to a pure content distribution network. A lot of the time, people put up trailers for work they're doing on places like Vimeo/Youtube, and if you gave them a way to sell their final product (and collected VERY low fees), that would be amazing -- I don't know that there's anything like that now. But maybe that's more of a future move, if you choose to, focusing on people with successful youtube channels is a good start.
[EDIT] - Also, be very careful, because a service like youtube could instantly create an integrated competitor that would make it very hard for you to compete. There IS however, value in being multi-platform, that way, no single platform's integrated competitor could take you out of the picture.
I'm no seer, but in the future, I think content distributors will want to distribute content over as much networks as possible. As youtube is rolling out paid channels from distributors, I think the creators of that content (or any content for that matter) will look to even make more money (obviously) by being involved in more than one distribution platform. I don't work in the financial sector, but more platforms pretty much looks like more income for any content creator.
I say that to say this: the more platforms you support, the more attractive your product looks as a general solution to the problem -- "I put my extra content in one place, and all my viewers can access it, no matter how they view my work"
[EDIT 2] - I just took a look at your site (dug through your submissions) -- in my honest opinion, you should build that site out. slap a bootstrap theme on it, and make a proper landing page out of that (though KEEP the super easy upload -- fast examples/usage is awesome, maybe just give people the option of making accounts after you give them the link, if they're going to be doing it often)
I see a ton of places this could go, but it all depends on what you want the service to look like -- I'm just spouting stuff out