Good to see more alternatives are coming to physically attending a conference or seminar. Waxxi has a nice and interesting 'interactive podcasting' service, but I prefer events within Second Life since it still allows you to have converstations with (groups of) other attendees in a manner that very much resembles a real life experience.
"I'm over visiting Shel for a podcast on Waxxi. There are almost 1,000 people signed up, which is just freaky. It's like giving a speech at a conference only from Shel's kitchen table. (UPDATE: Jeremiah Owang blogged the podcast, which was interesting because it ran like talk radio — people could come in and ask their questions over phone and there was a chat room too, I really liked the format; Mish in Toronto also blogged it; so did Peter Dawson, damn these posts all went up fast)."