The marketing program I'll be using works with keywords in order to help me select the videos that will give me the best targeted audience as possible. But in order to know the keywords I should use, I need to aslo be aware of who my audience is. Any other suggestions on what you believe motivated sellers might be into on you tube????
This depends on what you've found in your research (if you know how).
I, myself, have several 1 place rankings on the search engines (most notably, Google), as well as 3-4 of the top rankings on the 1st page for certain keywords. I've done it for my sites as well as other investors' sites.
Although YouTube is an excellent lead source, it has been my experience that folks aren't looking on YouTube for someone to buy their house. I've yet to use it for my marketing anyways. That being said, I'd still recommend using it. Google not only loves YouTube, but now owns it.

If you're going to use video, I suggest submitting your video to tubemogul.com. It will post your video various other video sites....YouTube included.
The key is to put yourself into a seller's perspective. What would you type in the search box if you were wanting to sell your house? By simply asking how a seller got my number when he or she called, they said they got if off the internet. I asked them what were they typing to get what they were looking for. The majority used the terms "we buy houses", "we buy houses (state)", "sell my house", "sell my house fast". **This is without using quotes when entering the keywords into the search box. 99.9% of web surfers do not use quotes when searching for something.
Hope this helps and good luck!