Memo key is used to read encrypted memos (You can encrypt memo if you add # in front of message).
I never knew about this functionality until now. This is kool. Lemme try how this works in action by sending you an encrypted memo.
Update!
Oh no! There's no way to reveal my private memo key. Something's wrong with the Steem wallet?
Yes, Steemit and blocktrades, smartsteem have protection. But @bittrex don't have it.
I think you need owner key to decrypt memo key.
I don't know Slavoj Žižek. Why?