Maybe this is outside the scope of the discussion, but with respect to synchronous streams, I can think of many times where I am browsing websites and opening new tabs as I'm e.g. reading an article when all of a sudden something, somewhere, starts playing audio. I didn't try to initiate any audio stream, but now there is, say, an embedded video playing on some tab somewhere, and I can't find it. I'm not sure what my point is, but it seems like there are two kinds of "synchronous" streams -- those the user expected to happen, and those that the user didn't. The latter case almost blends in the definition of asynchronous streams.-Scott