This is an interesting enquiry for me because I am quite good at committing to turn up to stuff but repeatedly find it difficult for online events. It is possible that for online learning I view that it should always happen at my own pace and timeframe and so the online events are more optional than physical ones? Or I know there will be a recording so I get a second shot? Perhaps it is just that the ease of access means I do not have to devote thought to planning my route to the venue and thus I don't schedule it so clearly.
I am struggling with this same issue when running teleconf/virtual seminars for PMRI. The academics are quite good at turning up if they say they will, but not so the practitioners. I am thinking that even with e-reminders, if you are at your desk right up to the moment (or even during) the engagement you are seen to be interruptible and free to work on other things.
So, I guess there is a question here: who (which type of participant) has the best attendance record for turning up for online events? [I am guessing participant categories to be: (1)physically present at a shared location (school); (2) self selected work location (home office, library, coffeeshop); (3) at workplace; (4) at home (leisure time).]
I'd love to know if there is any research on attendance and participation rates for both information and for credit events. A job for PLE methinks.