OK, so here is a way of posting longer stuff on BlueSky. Kind of.
You see, the underlying protocol - the AT Protocol doesn't really limit the number of characters in your messages. It is a general protocol for networking. BlueSky is one particular site, owning servers and the domain bsky.app, but it is a (founding) part of an ecosystem that could grow much larger.
Whitewind seems to take advantage of this. The stuff you write here on whtwnd isn't really stored by whtwnd – if I understand all that correctly – but rather by whatever fragment of the AT protocol network is handling your data. Which at the moment is, most likely, BlueSky. I think. Actually, not sure whether I understand it correctly.
In any case, you can use the Whitewind service to write blog entries in markdown, which is nice. Markdown is currently the main format I use to write basically everything – software, documentation, scientific papers, books, even sometimes e-mails.
So there. I wonder how the commenting works, so let me try this out right now.