There are a lot of places on Steemit that say this, but here is one more, because the problem continues and I don't want to see you get hurt:
DO NOT PASTE YOUR PRIVATE ACTIVE KEYS IN TRANSFERS!
If you're using your private memo keys, you're protecting your account to some degree by not using your master to make transactions. However, ALWAYS check your copy and paste contents BEFORE you enter the memo and submit: if you paste your private active key there, you are handing out control to your account... publicly and transparently, TO THE WHOLE BLOCKCHAIN.
Let's go over this one more time, because it's so, so important, and I know some people get a bit confused about this sort of thing. When you transfer money to and from Steemit to Bittrex, Blocktrades, Poloniex, Hitbtc, to another user, etc...
Do NOT Do NOT Do NOT use your private active key in the memo field. (I can't make this bigger, or I would.)
Before you copy and paste anything on Steemit, do it into a notepad or word document first to make sure it's actually the thing you mean to paste! If you copy your key to log in, be extra careful and take the extra step that the memo you need to copy actually copies — we're so fast at hitting control-V-enter that it's just way, way, WAY too easy to mess this one up. And if you do, you are giving access to your wallet out to everyone on the chain. One extra step, but so worth it, compared to having an emptied wallet.
Here are some scary facts: I found 65 transactions in just the last 3 days without even looking hard. I or anyone else could have taken all the money out of and transferred anywhere I wanted to. Those accounts had just under $10,000 in them when I checked the wallets.
Anything you type in that memo field is visible on the blockchain for all to see. It doesn't go away. You can't take it back — please be cautious when making transfers! One or two extra seconds to check your copy/paste will save your wallet.

I'm Jeff, and I'm @followbtcnews.
I'm a top 30 witness, along with my project partner @crimsonclad. Feel free to reach out to us on Steemit Chat or Discord any time! If we haven't earned your vote yet, please take some time to look at our tools and our work. We hope you decide to place a vote for followbtcnews at https://steemit.com/~witnesses
This post made from https://gosteem.com