I'm not entirely sure what your question is - are you asking how Google/Facebook are proxies for physical thing?
Google, at its core, provides a service that helps you do physical things more quickly. If I need to replace the cruise control buttons on my car, I could go to the library and source a manual, or I could just search Google.
Facebook marketplace increases the efficiency of trading physical goods.
The Facebook feed is probably most akin to cigarettes.
