Assuming Snoke is Darth Plagueis:
- The scar on his face is from Palpatine trying to kill him with a lightsaber.
- Somehow he did not die when Palps supposedly killed him.
- In episode III, Palps mentions that Plagueis could use the force to create life. Some have suggested the possibility that Plagueis "fathered" Anakin Skywalker through the force given that he "has no father". Whatever be the anomaly that spawned Anakin, it had given him an extremely powerful connection to the force, as noted by Qui-gon and Obi-wan. Who else has a powerful connection to the force? Well.... Rey. She didn't even need a teacher to learn how to pull mind tricks on stormtroopers and telekinetically grab a lightsaber out of the snow. If Snoke is Plagueis, I think it is reasonable to consider that he created Rey, especially concerning the mystery around her parents.
- Snoke's Wookiepedia article says that he values the "balance of the force". The prequels frame Darth Vader's killing of old palps in episode VI as "bringing balance to the force" (the whole prophecy of the chosen one thing).
So that's my insane theory that probably isn't true. I thought it would at least be an interesting idea to share.

