> Not only can Facebook say you are a Trump supporter, but they can know by how much and as time series!

That's a fascinating insight. They also have the geographic data and could slice/dice to get a sense of electoral college. After the systematic polling error that caught everyone off-guard, we will probably see some innovations in the next 4 years that will get incorporated into the ensemble models (e.g. 538). Perhaps Facebook will release some sort of sentiment data. Although that may get a little creepy.