We also use Olark chat on our site, which besides giving us the ability to chat with our customers easily online, we can see what pages the customers are visiting in real-time, during our chat. I've chatted with scores of customers this way, and it's typical for most every user to jump all around the site to get a good feel for 'how it works', 'what it does' and 'how much does it cost'. It's helpful if you have an obvious "sign up" link incorporated on every single page of your website, so no matter where on your site a customer decides they want in, they can do so easily.
I can say that adding that video did not hurt conversion, but it also didn't substantially increase conversions either. I do still think it's an important aspect of any new online service, regardless of your implementation (video, graphical, text).