We launched our product to the public on Hacker News with the title "Show HN: Turn any device with a browser into a security camera" and a link to our app. We didn't have high expectations. We had posted on a few subreddits before and only got a handful of signups. Boy were we wrong! What a response we had! We ended up staying on the front-page for almost 12 hours! The highest that we made it was #15, but that was enough to get us ~6000 unique visitors to our website and 130+ signups. We answered questions and responded to people throughout the day. Hacker News has an amazing community with a lot of intelligent and insightful people. We compiled a list of feedback and discussed/prioritized them the next day. This would bring about one of the biggest changes to our product. We decided to change our business model from free trial to freemium (free forever with optional paid premium).
My partner Jordan also wrote a blog post about what we took away from this experience. You can check it out here: https://medium.com/@jdmcrae8/how-to-get-the-most-out-of-sharing-your-product-on-hacker-news-860d333488d7