The instructor is very active, participants are less so. Quality is perceived to be the instructor's obligation. You usually evaluate the instructor or presenter. You are often not evaluated. Here's what to expect in online learning.
Content is delivered differently.
It will not be given to you. In an on-site seminar or class, the teacher talks and all you have to do is listen. Online, you have to initiate learning and actively go get it. You have to figure out what you want to learn, because there is so much material. You have to read the material.