I can't answer for other providers, but for the on-line seminars On-Track have a simple question, answer, discussion format in breakout groups of around 10 which lasts for 2 hours. The tutors nominate a delegate to answer the question which can then lead to a wider discussion. Before Covid, the seminars had a morning of presentations given by groups of delegates base on topics they were given the previous day. When the seminars go back to being in-person, I suspect that what they'll revert to.