This is the latest phishing scam on Steem blockchain. The scammer, @girafarid of Iran, purportedly representing the witness exnihilo, comments on posts saying that exnihilo would gift you 100 Steems if you vote for the witness. A phishing link is given for you to vote.
If you are to click the link and vote for the 'witness' you would certainly be sharing your keys with @girafarid.
What if you have already voted for "exnihilo"?
Change your master password and keys immediately here.
Also check to see whether someone other than you has powered down your account. If yes, undo it.
What else can you do?
Mute @girafarid to prevent his comments appearing on your posts.
Hope the above helps, especially the newcomers.