Youtube is also a search engine and you can optimize your channel on it too. Today if you want to increase your reach of video then you need to move on your social media network. SMO is the best part to share and engage with more and more people. Share or submit your video on different different video submission website with relevant and unique description.

I'm sure there are sites in which you subscribe to others and they subscribe back. No idea what it is called, but I'm sure you could make do with these until you reach a certain goal.

Use social media and free classified ads sites like http://www.krreddy.com

Any social media is a great way to advertise facebook, twitter etc...