Saturday was Invisible People.tv day at YouTube. InvisiblePeople.tv is a site/project that utilizes social media tools like YouTube, Twitter, Facebook, and MySpace to spread awareness about the growing homelessness problem. The channel was featured on YouTube's home page over the weekend, and YouTube discussed it in a company blog post , speaking with Founder Mark Horvath. "We're always inspired by the people who use YouTube as a way to document how the other half lives,