We had good internet (rare at conferences) and pretty positive feedback about the Siggraph stream. The popularity really shouldn’t affect the watch-ability - we just stream the video up to the provider (Ustream in this case) and they restream it out to as many users as want to watch.
What issues specifically did you notice? Was it worse than NAB?
The IBC stream (since it originates in Europe) is run through different equipment and providers than Siggraph. We’re also planning to make some changes to the NAB and Siggraph streams before NAB next year, but it would help to better understand what issues you encountered so I can sort out whether they were related to our show setup or the streaming provider.