So, a lot of people don't realize that many of the sites we frequent are operated by very dumb algorithms. They have to be dumb because if they were complicated, that'd start to cut into site load time and usability, and that's a non-starter. Especially when your site serves millions of people a day. YouTube definitely has a dumb algorithm it uses for that reason.
That's GREAT news for you.
But here's the bad news ...
Getting stuff to "go viral" is often a crapshoot. In fact, Buzzfeed (often paraded around as "experts" on viral marketing) often has to make changes to content on the fly once its posted because they don't know if it'll spread or not. Their goal is to raise the CHANCE that it'll spread.
So I'm not going to sit here and tell you to "make good content" because that's bullshit. Shit content spreads better. That's why Buzzfeed steals from Reddit and HuffPost and Business Insider run the crap that they do.
What I will tell you is that you want to trigger the YouTube algorithm without being shitty about it, regardless of the kind of content you're uploading.
You can go and buy YouTube views off of eBay and Fiverr, but Google is getting pretty good at catching that shit.
What they're not so good at catching is what I'm going to recommend you do to spread your stuff: Bribe people.
If you want your stuff to "go viral", and I'm assuming you did the press outreach and got all your friends to share the video on Facebook and link to it on their blogs (this is a must because it feeds the algorithm), the other thing you have to do is get people to sit and watch the video IN ITS ENTIRETY AS SOON AS IT GOES LIVE. Then, have them leave a question or a comment (although, pre-Google+ integration, questions seemed to have done better.)
Doing all these things (not some, ALL) will trigger the algorithm, and as more people view the video, it'll start to surface higher and higher and spread into more sections and categories on the YouTube site.
I'm only sort of kidding on the bribery part, but you get what I'm saying.
What to do :
1. When the YouTube video launches, there should be a lot of activity that occurs as soon as it goes live.
2. Get your friends to share it on Facebook and blog about it (the other social networks really don't matter, as far as I can tell at this point in time).
3. Get the press / blogs to write and link or embed the video
4. Get as many people as you can, through whatever means necessary, to watch the video and leave a comment.