Interesting. And to render the html you can use cutycapt. Which is in the Debian repos too. I just tried it, and this rendered a nice diff of two pages for me:
This is why I love HN. Someone launches a web service with a flashy site, lots of marketing blurb and monthly plans from $10 to $200. And in the HN comments thread, two random people reimplement the functionality in three lines.
I don't actually see the problem here. They provide a real service, so they can demand real money. There are multi billion dollar companies that do less for their users.