If you were active on crypto twitter you probably have seen those tweets about fake giveaways. They are old news now and I don`t think people are falling for them anymore.
So I was very surprised when I saw this comment on afaik the biggest Steem site on Facebook
Huobi is a pretty big chinese exchange I am using myself. It works the same as other exchanges that through the memo they can identify your trading account and deposit the Steem if you withdraw to them.
The only good thing is so far has nobody fallen for this as 