#33: using Twitter for long-form content
https://news.ycombinator.com/newsguidelines.html
Regardless, all you need to do is scroll down. It's clearer than HN's trees.
Had you seen it on a blog post, would you have typed in your email address into the inevitable popup modal? Gaining some Twitter followers and a bunch of retweets is better than gaining 0 emails from a hard-to-discover blog post.