Hi,
You have to register your APP with facebook developer. See this official documentation to register app.
https://developers.facebook.com/docs/web/tutorials/scrumptious/register-facebook-application/
Thanks
When, I read this it sounds more that it is you – the developer of the plugin, who need an App-ID?
Well as you know this is optional!
This is only if there are any issues in rendering the facebook plugin. The app ID is for facebook to recognize from where and by whom the facebook is being accessed. They need facebook user credentials and the website link where the plugin has to be used.
So I can not register APP for every user of this plugin!
Hope this makes sense 🙂
Cheers!