Statistics that I have seen suggest that live webinars or hybrid webinars (recorded webinars with the host standing by to field questions as they come in) do better in terms of getting signups than recorded webinars do.
There are also statistics that say that many people do watch replays of live webinars (which of course, are recorded). From what I gather, people will sign up more often for a live event even if they know they won’t be able to attend live. There’s always the chance that the technology for the recording may not work, after all. A recorded webinar, however, doesn’t have that component of the unknown technical issues, so that could account for the signups being less.
From everything I have read, it is suggested that you do your live webinars at least a few times before starting to utilize recorded ones on a large scale.
All that being said, many of the big guys and gals of the internet marketing world use recorded webinars, and I personally enjoy trying to figure out if the event is live, recorded or a hybrid. 😉
Hope that helps.