If you log into steemitwallet.com you can get your private keys.
Your master key (or password) provides access to all the below
Your posting private key lets you post transactions to the blockchain.
Your active private key lets you transact - power up, send steem, etc
Your owner private key lets you change your recovery account.
Your memo private key lets you read encrypted memos (transfers sent with a prefix of a pound symbol (#)
Hope that helps
Think of this as having different locks to different sections of your house.
RE: WARNING: Phishing is Back!