No, my Steemit account has never been hacked and I wish it remains that way. I still remember what I passed through when my Facebook account got hacked, though the worth of a steemit account can't be compared to a Facebook account, at the least I have experienced the pain created by the Denial Of Service (DoS). being unable to login and use my account while an unknown person was using my account to strike fraudulent deals.

My opinion concerning dubious links offering rewards?

Most successful hacks are a result of cleaver phishing techniques sandwiched with some form of social engineering, keyloggers and malicious software that creates a backdoor into your device.
On Steemit, such often comes in the form of a link that offers to give some kind of rewards if clicked. In reality, such linked are linked to a series of malicious codes that will exploit a vulnerability on your device,
In most cases, clicking on such a link will disable the "ask for permission" option on your device so that once the download of the main keyloggers or spyware that will steal your username, posting and active key. This information will then be send it to the hacker.

Yes, your account can be hacked by a single click on a phishing link.

My recommendations to prevent an account from being stolen or hacked?

It is best not to click on links that are unknown, links that have mouthwatering promises are often set as baits and any link that takes you outside steemit should be viewed as suspicious untill proven innocent.

Try to read link destination paths
Learn how to read a links path which is easy when the link is kept in the open. By that I mean a link that is dropped like this:
https://en.m.wikipedia.org/wiki/Phishing

It is easy to tell that this link will be taking you to the Wikipedia website, under the wiki section that discusses Phishing.

But if the link is formated, such that it's path is not openly shown like this one:
Free TRX

Press and hold on the link till it display a menu like this:

which will give you the Parth/address the link will be taking you to, or action to be executed.

You can copy the link and pest it in a text editor.

This link called free TRX will be taking you to the kaspersky.com where you have the definition of social-engineering

keep your keys to yourselves
Your steemit keys are your personal property. Do not give your keys to anyone else, and be careful when trusting third parties with sensitive steemit keys.

Generate new keys
After using a key for a while, use your master or owner key to regenerate new sets of keys. This is something you should do if your phone is stolen or snatched.

Why do some accounts get hacked?

• An account could get hacked if you kept your keys with a third party and the third party has been compromised.

  Better keep your keys alone and don't trust anyone with it. Keep an eye on your account by regularly checking your Steemit account for suspicious activities.

• Your account could get hacked if it was created for you by someone such that the person has your keys and has now gone rogue.

  periodically change your keys, ask steemit to generate new sets of keys rendering the old keys obsolete.

• if your keys got exposed, your account could be hacked. This could happen if you copy the key and paste it in an input field that that has no encryption or mistakingly sent it to someone. It could also happen if your keys are written on a diary.

  Quickly use your master password to reset all your keys. If you should write your keys on a diary, use a type of data encryption technology to protect the key.

• Your account could be hacked if you login on a device that has an outdated operating system or web browser. Or a device that has been compromised.

  Always update your device and don't login using a device you are not sure of and once a device flags an error, be quicke to respond to it and don't ignore it. If you are using Android, get safe apps from the Google play-store.

• If the Email that holds your keys is not adequately protected with a full proof two ways authentication, you could get hacked.

  Activate a two way authentication on your Email to protect your keys.

To anyone whose accounts are hacked?

Immediate action
Of the hack is ongoing or is still within the 30 days limit, I will suggest an account reset in the Steem world.com site.

Words of Consolation
It may not be as a result of your negligence that you got hacked.
Try recovering the hacked account as the reputation you created using that account is a very valuable resource, assuming the funds have been lost.

Prevent it from reoccurring
Change your password and learn how to keep your account safe.

What you should do if your account is being hacked

Immediate action
I will end any progressive power down and immediately go for a reset of all my keys.

Buy time
Depending on the feature that will respond or not, I may also delegate my Steem to any user so as to buy me some time.

Recover Account
Now that the hack is still in progress, it means I still have the opportunity to go to Steem would and ask for a reset.

Conclusion

Incidents of hacks have become reoccurring trends this days, it is good to take proactive steps to guide against being hacked and knowing what to do when a hack is in progress can save you a lot of pains, frustration and heartache.