What you say makes sense. I guess I am blind because I for the love of me can't think of any decent twists to make this worthwhile. As you said, you never EVER click or signed up for anything, neither have I, and I can't think of anything that would deter people from watching and to go sign up for something.
I went into this method following the OP pretty closely, with little twists such as custom titles/descriptions/etc.. I've tried watermarking videos, I've tried just name of my website in the title. I made a custom bot, as well as running Adult Tube Site Submitter. I've uploaded thousands of videos, spent a decent amount of time and money trying to milk this method, and I've had VERY little success. I've made about $10 total, and haven't had a lead in 2 weeks.
I would love to hear any ideas people have on twisting this method to make people want to actually stop watching porn and click a link and sign up. Because as you said, people don't want to stop watching, click a link, and sign up while watching porn.