Consider adding more collateral, especially around adoption

[earth2marsh]

The CSL has been out in the world for a few years now, so as a potential user of the spec, it would help me to understand what projects are using it.

Or if there are alternatives to consider, it might help to explain what those are and why you would still choose the CSL in certain situations. For example, if your spec is using Apache or Creative Commons license, what are the downsides you face when using those licenses? Presumably they are meant to cover code or content, while a spec sits somewhere in between?

I wonder how much it might help the readme to link to the original announcement in order to provide some background? And even a "Four years later" post might be good to help explain how it has been used and what its future looks like? That could address some of the social proof mentioned at the top of this issue.