Back in ~2001 I ran a fairly popular blog commenting system - back then most blogs didn't have built-in comments, so I offered javascript embeds to add them to posts.

One day performance started to go down rapidly, and within a few days my host got in touch about unusual CPU usage.

I tracked it down to a series of random blogger.com blog posts with colossal comment threads measuring in the thousands. Each post only got comments for a single day, and all of the comments were in Japanese. The blog owners seemed very confused.

Turns out Japanese schoolkids figured this trick out 25 years ago.