Also, many of which were essentially the same, despite the different names. Theoretically a message made in Google Talk in 2005 would have been visible in chat

Also, many of which were essentially the same, despite the different names. Theoretically a message made in Google Talk in 2005 would have been visible in chat history through migrations/rebrandings to Hangouts and Chat. You'd need a fair bit of research and a flowchart to explain them all.