Which protocol or open standard do you like or wish was more popular?

There are a couple I have in mind. Like many techies, I am a huge fan of RSS for content distribution and XMPP for federated communication.

The really niche one I like is S-expressions as a data format and configuration in place of json, yaml, toml, etc.

I am a big fan of Plaintext formats, although I wish markdown had a few more features like tables.