From discussion with users of Second Life, particularly during the iCommons iSummit in Croatia a few weeks ago, it is interesting to note that the participants who weren't there in RL felt more inclusion when they attended in SL. Although I must admit to finding the whole thing very disconcerting - particularly when I appeared within SL asking a question and my colleagues in SL spotted me and emailed photos..
The entire iCommons was very state-of-the-art with regard to SL and was simultaneously broadcast within the virtual environment. Together with questions in the conference being taken from both RL and SL and put to the speakers. The SL attendees that I have talked to all argued that the event felt more 'inclusive' than a mere video stream online.
Although there is much to SL that is problematic, events such as these raise interesting questions about widening participation and challenging our notions of what it is to 'attend' or 'witness' an event. Certainly when one thinks of a spectrum of participatory media, I think the SL is certainly much better than the monological online media either as youtube feeds or webstreams.