Yes, content could be distributed using in encrypted memos while dummy posts with dummy accounts as beneficiaries could be created to tap into the reward pool completely anonymously. All kinds of shenanigans could be handled by an app on behalf of the users to tap into the reward pool anonymously. Too bad Steem has no smart contracts, because much of that trickery would have to be done off-chain. It's not easy to create a Steem app that hides all user data from the public but it is completely possible. It is possible to do multisig-transactions on Steem.

See: https://steemit.com/piston/@xeroc/piston-how-to-use-it-for-multisignature-accounts