Besides Session IDs and Session Tickets[1] which already exist in the TLS protocol. He could be referring to the Token Binding Protocol Draft[2] which, quoting from it's summary, "allows client/server applications to create long-lived, uniquely identifiable TLS bindings spanning multiple TLS sessions and connections".
Running Google Hangouts through Tor would work well as it uses https by default. As long as he's using a throwaway Google account, it seems good to me.
UW Madison represent! I took the course with this book, not with Remzi though. He is an amazing professor and this book gives a very good introduction to OS, especially Linux OS internals.