Make it funny/stupid/sexy enough, and people will watch it.
A couple of good examples of this:
http://www.youtube.com/watch?v=6xfBNxNds0Q http://www.youtube.com/watch?v=owGykVbfgUE http://www.youtube.com/watch?v=USYa5iH3f3s http://www.youtube.com/watch?v=JJmqCKtJnxM
Don't know if the latter was launched as a viral campaign, but my point is that you know it and the brand it was from if I'd phone you up and shout "WASSUP".
Marketing is a lot scarier that you think.
I doubt that most people would. They know the meme; they remember the commercials, but what brand? I mean, without looking, I believe it was beer, but I'm not totally certain even of that.
My memory (usually block it out to begin with) in recalling brands from commercials is terrible so I'm inclined to believe most people would remember. But we are both just guessing.
If we only knew the formula for viral videos, ad agencies would be all over that. Unfortunately/Luckily, there is no such formula..