Welcome to the Q&A Forum

Embedding your Youtube video on your site will help promote your Youtube video on organic results in Youtube and Google. The number of embeds is definitely one of the factors that is looked at in the Google algorithm.

Ideally, if you do have any contact with the webmaster you'd be better off asking them to change it. If you don't, starting to network with people already willing to link to you is a great way to get more links anyway. If you really don't want to try and speak with them (and again, you really should) then I have done something similar with affiliates; when they send a visitor I send them to a co-branded page based on the referral header, and haven't seen anything bad happen. Although Google is getting better at reading javascript it still doesn't seem to follow links run in real time. As you're not intending to deceive the bot your use of it is fairly legit, but I couldn't tell you how it'd be interpreted once the datacentres have a look at it. Here's the guidelines - http://www.google.com/support/webmasters/bin/answer.py?answer=66355 - up to you if you think you're breaking them

I consider a site is  passing the "I'm brand" level when google will display site links. That' susualy based on incoming links - authority overall. So in my personal opinion to get there you need a few powerful, " patient zero " links (very very high authority sites that will link to you - in that category I also include facebook.com, linkedin, twitter and digg - that's a good place to start). You also need several additional niche related strong links in order to "qualify". That is my personal view on the brand signal thingy. Hope it helps.

I'd add that if it's a truly great piece of content it might not hurt to get some help. A lot of link building agency's nowadays rely heavily on social networking and have large if not HUGE networks to lean on and this could definitely come in handy. A one-time push of one piece of content probably wouldn't break the bank. Outside of that - I'd say a lot of the tactics @PH292 mentions but don't be afraid to jump in to your own social circles and push. If it's important and worth it - this is probably time to pull out the "pretty please RT xyz" dm's, messages etc.