Ask you IRL friends or colleagues from your job "hey, do you happen to have an HN account?" If the discussion is related to a public project, like in the examp

Ask you IRL friends or colleagues from your job "hey, do you happen to have an HN account?" If the discussion is related to a public project, like in the examples in this comment: https://news.ycombinator.com/item?id=47303604 https://news.ycombinator.com/item?id=47303604 ...you can use existing communication channels (website, readme on github) to ask people for an invite to participate in it.