Conferences and workshops are often great - getting together and being together is an ideal setting for doing research and learning things. However, there are various reasons to encourage the possibility of having conferences and workshop through "cyber space". The cost of travel, in terms of time, money, $CO_2$, is large.

Q1: My first question is about software that makes it possible to run lectures with long-distance participation. What are the features and what are additional features we would like to see.

Q2 My second question is about what could be good ideas for running a long-distance workshops or conferences. (This question is mainly experience-based rather than opinion-based.) Hybrid setting with conventional conference that allows some participation from cyber space? Completely cyber conference where each participant stays in his office/study.?

I have some experience with the TCS+ seminars which are completely in cyberspace and participants from the audience can ask questions. They work rather well. (But only a few participants per talk.) I am not familiar of similar things in mathematics.

Very related question: Tools for long-distance collaboration (This is about tools for long distance collaboration, in general. Not specific to seminars/workshops/conferences and also asked nine years ago.)