In the past few years, I've done my share of online presentations and online training. (You can call them "webinars" if you like, but I'd prefer not to add that word to the lexicon.) Here's the problem with online presentations: there is very little attendee/presenter interaction, and current technologies like WebEx and GotoMeeting provide little help. If you teach online classes long enough, you'll start to realize that this lack of connection, this lack of co-presence starts to wear you out.