Notebin is great to practice posts with markdown indeed! Using Nosbin now, might switch over, thanks!
It's like a micro blogging tool with markdown where you can create blog posts as notes that get published as an event and is authorized using Alby (Currently it only works with Alby because of the specific event that it uses. It doesn't work with Nos2x yet)
For example this is my pubkey https://notebin.org/u/npub123tev4ahur7e6uzz7exyhj3ql0vt039ga6skvxt9tuxytp26pk4qxfaur9 and you can see the notes/blog posts I submitted.
You can then also setup your LUD-06/Lightning address to receive tips (inbuilt integration on Notebin).
Pretty cool stuff.
Discussion
Nosbin is great too! been using it for sometime now.