Andreas Antonopoulos has done a live talk @ DG717 in San Francisco which concluded roughly 1 hour ago, it was live streamed to youtube and now the recording is available for your viewing pleasure.
The topic's include immutability, reversibility, and the difference between hard promises and soft promises.
The Event was a meetup group which had 303 registered users, not sure on the official count although you can hear from the crowd it was a massive turn out.
Andreas
Technologist, serial entrepreneur, engaging public speaker, and all around Bitcoin guru, Andreas is one of the most well-known and well-respected figures in bitcoin. Author of “Mastering Bitcoin”, he literally wrote the book on bitcoin. He is a widely published author of articles and blog posts on bitcoin, is a permanent host on the popular Let’s Talk Bitcoin Podcast, and a frequent speaker at technology and security conferences worldwide. As a bitcoin entrepreneur, Andreas has founded a number of bitcoin businesses and launched several community open-source projects.
You can find out more and watch some of his past events at https://antonopoulos.com/