But I have downloaded and examined the syllabus materials for the talks I'm most interested in, from RootsTech and from Legacy Family Tree. This is my first step, because looking at the handout helps me prioritize my viewing, and determine what I want to watch (and what I don't want to watch at all or not soon). The syllabus gives me a good idea of the speaker's main points and usually includes sources or additional reading/viewing related to the main points, if I want to follow up.
With the syllabus in hand, I can follow along as I watch and check relevant websites or sources. I also like to digitally file the handout and look at it again if I want to refresh my memory, rather than rewatching a webinar. If I choose, I can view the RootsTech talks on YouTube, where viewer comments are visible below the video.
On Legacy Family Tree Webinars, there's an option to download the syllabus and download the chat log. Sometimes the chat includes interesting comments or suggestions. The syllabus materials are always helpful and often quite detailed. And I can use the syllabus to decide where in the webinar to focus my attention if I only want to watch a segment, not the entire video.
This method might not work for you, but as a print-oriented Baby Boomer, I like to get the gist of something by checking the paperwork before investing time in viewing.