Thanks for the feedback -- definitely agree on the demo! Based on some feedback from one of the Show HNs, I'm planning to make some fake little chat bot, so users have something to interact with (albeit in a very scripted/formulaic way) instead of sending a link to a friend. The chat bot will replace the static demo entirely.

It's definitely a style change first and foremost. I got sick of this pattern: friend sends message1, message2, message3; I respond reply1, reply2, reply3. And then they probably reply to some (if not all) of my replies. Usually it's pretty clear which message corresponds to which topic, but it's always messy. With XpanXn, it's explicit and visually obvious.

Each topic column is a fixed width. You can pan around the chat canvas and zoom in/out exactly as you'd expect! In fact, another motivator was knowing that a lot of people like really small font sizes on their phones. This way, you tailor font size just by zooming in/out. There's definitely some opportunity to improve that, but for now, I think the ability to pan tends to most of that concern.