Rumors flew yesterday about today’s YouTube announcement. Some thought it would be high-definition videos (long desired); others thought it would be a deal with Hulu (which would have been cool). The real announcement was an opening up of YouTube, turning it into a service that could power your own application, site, whatever, via new APIs.We try really hard to make YouTube as open as possible. Anyone can upload and view videos, which can be embedded anywhere and viewed on all kinds of different devices. And,