Someone recently got his account stolen after following a link from Hive account@twinkledrop

Here is how the hacker proceeded:

EDIT: Seems like steemit updated their code and phishing links are now displayed in red. Great news !

The hacker posted a nice comment on one of his post saying:

(This is a demo)
Someone stole your post, you need to report him :
https://steemit.com/@potential-plagiarist/stolen-post

Here is the trick:
If you click on the link, you will be redirected outside of steemit.com, on a site that looks like the real site (it's fake) and you will be asked to login like you would on steemit.

The hacker used the fact that you can format a link in markdown like so:

[ LINK YOU SEE ] ( REAL LINK )

The link in the demo is formatted like so:

[ https://steemit.com/@potential-plagiarist/stolen-post ]
( http://www.bitsharesfcx.com/ )

How to prevent this from happening again

One way to prevent such hack in the future would be to warn users when they follow a link that redirects them outside of steemit.com

What to do if your account was stolen

Start there: https://steemit.com/recover_account_step_1