I just answered this at https://news.ycombinator.com/item?id=34719677. In the future, please do as https://news.ycombinator.com/newsguidelines.html ask and send such questions to hn@ycombinator.com so we can actually answer them. I only saw these threads by accident!

Btw I'm pretty sure it isn't getting more common, except in the sense that threes are getting more common in this random sequence:

  arc> (collect 10 (rand 10))
  (4 7 3 3 1 9 3 1 2 0)

Where? In what context?

Just as replies to posts. Here's one example. It's hard to search for: https://news.ycombinator.com/item?id=34694407

I can't see a single '*' in that thread and haven't seen any other '* * *' on HN. Do you have any third-party browser plugins installed that might cause this?

Maybe the users try to write Markdown to make words italics (https://news.ycombinator.com/formatdoc)?