alt Hacker NewsHey! Wow, I knew about OpenTechCalendar but somehow hadn't realised (or likely forgot) how close to home it was! I'll definitely reach out for a chat at some point.
And thanks for the tips - I completely agree on the point about data being held hostage, and on the openness of data - it's one of the more frequent complaints about Meetup. I've recently added an API for event creation, so it won't be hard to add another endpoint for listings (at the moment, we just have an embeddable widget [1] showing your next 3 events).
ICAL is a brilliant suggestion - I've had a few requests for that already, and it's especially interesting in the context of opentechcalendar. I'm very interested in ActivityPub and all things fediverse as well - figuring out how to integrate these ideas into the platform is one of the next items on my TODO list.