On a similar line of thought, I'm wondering if say someone releases a great open-source Pulumi library (e.g. for setting up a production-ready k8s cluster with all the awesome sauce). They write this library in TypeScript. Can I reuse it from Go or do I need a similar library that's written in Go?

This (using a Typescript/C#/etc module from Go/Python/etc) is not currently supported, but is on the roadmap. You can follow this issue for updates - https://github.com/pulumi/pulumi/issues/2430.

Note that you can use stacks created with different languages today. For example, you could create a networking stack in Go and a dependent app stack in TypeScript.

ok, sure. Thanks!