I would say that their rather different, classes tend to be structured events in which a group of people learn a particular skill where as webinars and conferences are all about socialising and networking with other people (that and listening to a few talks on various subjects). I would guess that online possibly is less social than offline as there's no face-to-face contact (it's going to be a chat room environment at best). However saying that the line up does look pretty good and for that price you can be sure that it's good value for money. My advice would probably be... why not? Your spending a bit of cash and getting to hear some decent speakers, granted it's not as big as one of the major conferences but then you pay more for those (travel, accommodation, tickets) so it really comes down to whether you're interested in what their talking about. I've not attended any online ones myself but I recently went to my first offline one so it was an experience.