On the iPad you don't have to install Silverlight, but you do have to install the proprietary Amazon Instant Video app -- so it's not exactly a better situation

On the iPad you don't have to install Silverlight, but you do have to install the proprietary Amazon Instant Video app -- so it's not exactly a better situation. They could replace Silverlight with a Mac app called "Amazon Instant Video" and that wouldn't make the situation any better. In the end, they need a streaming video client that supports DRM that the movie studios approve of. Additionally, as is mentioned, they also support Flash on desktops, which most people already have installed. However, the Flash streaming is not as great -- it most-likely uses RTSP, an older stateful streaming protocol, versus their Silverlight client likely uses Smoothstreaming (or similar), a HTTP-based adaptive streaming format.