Snoke is Darth Plagueis is so 2015 The more recent crackpot theory is that he was actually... Darth Vader returned from the dead as a kind of dark side evil twin to Anakin's force ghost, and that contrary to a light side ghost "one with the Force" the one feeding on the dark side could gradually regain life. Or something like that... Don't despair Kylo, grandpa's coming.

sigh. It's even worse than in the good old days of the "Senator Palpatine isn't Darth Sidious, it's too obvious" theory that endured all the way to the release of ROTS.

From the official info:

• Snoke is from a humanoid species but he's not a human.
• He's quite aware of what went on during the PT and OT, but wasn't a participant.
• His whereabout are secret and he doesn't have a permanent base. He has a "mobile base of operations" (likely a ship or station) from which he contacts his underlings. He's probably in the "unknown regions", beyond the chartered galaxy (lots of mentions of those.. Luke is also in one of the unchartered areas... and the Jedi seem to have begun in one of those zones... this speaks more and more of "lost secrets" no longer known to the Republic or Empire, to Sith or "modern" Jedi. I wouldn't be surprised at all that the explanation is that Snoke is from beyond the Republic/Empire areas, was there during both OT and PT and only recently became active in the galaxy's territories.

His existence is no secret, though.