I'm drawn to the warning at the top about it being a long post that clients may struggle with.

Realistically, it is not a long post. There is not a lot of text there. Sure it's long for a tweet, but it should be a cakewalk for a modern computer rendering text.

Yet for my 2021 flagship smartphone, rendering these 142 lines of text is a nigh impossible task. The page lags all over the place and my phone is now hot. What on earth is going on with this webpage? What colossal task is Mastodon doing in the background that isn't related to rendering this text?

I think it's a text layout rather than a text rendering issue.

This one is surprisingly fun, but I wish there is an option to choose a different map projection:

https://canidigtochina.com/

Entertaining starting points for some pointless browsing. I like the fact that they compiled the prospective list by downloading TLD data. DNS data is mined in surprising ways.

It hit me that there's a treasure trove of possible cool websites you can find just by looking at hostname and other DNS fields.