I've read that you can make a Google Apps Script that shows a Facebook Feed, and then embed this in a Google Site, but I can't find any more information on how to do it and I can't figure it out myself.
When I try to make an Apps Script web app with a Facebook feed I get errors like:
Uncaught DOMException: Failed to set the 'domain' property on 'Document': Assignment is forbidden for sandboxed iframes.
This is from copying the "Facebook Javascript SDK" and "Page Feed" from Facebook Developers into an HTML file and deploying it as a web app. I gather it has something to do with how Apps Script sandboxes your code but I don't know what I have to do here.
For that matter, even if I try to make a simpler Apps Script with some static HTML, when I try to embed it from Drive into the site I get an error "Some of the selected items could not be embedded".
The New Google Sites doesn't support Google Apps Script.
Related question: Google App Scripts For New Google Sites Release