Here is my site, it is pretty great. But I want to be able to comment on the material that other people have written.
This is pretty easy now with gatsby-theme-brain. All I have to do is setup a couple of parameters in gatsby-config, and I can quickly and easily link to and get backlinks from that other site.
So, for example. I know the author of Site 2 and we trust each other's opinions on books. So occasionally I will leave a note on my Books page about their list, or about a specific book. And then, when anyone browses Site 2, they will see the note that I have left.
Checkout the [[Books]] page for examples