LinkedIn is a popular social network that connects professionals, helps in seeking a new job or solve work-related problems.
General guidelines on staying safe at LinkedIn
First, always log in to LinkedIn via the secure page https://www.linkedin.com!
Second, do not post sensitive information: your passwords, secret work projects, etc. Do not post things that can harm you later. For example, "I really hate my stupid boss now" might get you fired if your boss finds out about it...
Third, do not trust all people who want to connect with you - there are many cyber-crooks among them. Be selective and ask questions, if needed, before accepting requests to join someone's professional network.
Fourth, always log off of LinkedIn after you've done visiting the site - otherwise LinkedIn applications and advertisers might track your browsing habits, and this is not that harmless! And do not expect logging out of Windows or restarting your computer to protect you there - you really-really need to sign out of LinkedIn to delete cookies that might allow tracking.
To stay safe, click your account photo on the top right and select Sign Out from the menu.
Configuring LinkedIn settings
To set your LinkedIn preferences, click your account on the top right and click Privacy & Settings (Review).
LinkedIn Profile settings
Profile tab opens first. Click Turn on/off your activity broadcasts.
It is recommended to keep your activity private to prevent unwanted people from seeing potentially sensitive data - for example, your current boss might not like you looking for a new job.
Clear the Let people know when you change your profile, make recommendations, or follow companies check box to be on the safe side in the future. Then click the Save changes button.
Next, click the Select who can see your activity feed link.
Limit the visibility to Your connections. Click Save changes.
You could also limit the visibility to Your network or Only you, but never select Everyone here - your activity on LinkedIn should be private.
Back on Profile tab, click the Select what others see when you've viewed their profile link.
The recommended option is fine with most people, but those who need to keep their actions private should click the Anonymous profile characteristics such as industry and title radio button.
Don't forget to click the Save changes button! 
Next, click the Select who can see your connections link.
Most people should choose the Your connections option here, but those needing to keep the details under cover should choose Only you instead.
But remember, shared connections will always stay visible!
Click Save changes.
Open the Change your profile photo & visibility link.
Select either the My Connections or My Network option here. Never use the Everyone option!
Remember, if you message someone on LinkedIn, your profile photo will be displayed in the mail.
Click Save Settings.
Back on the Profile tab, click the Edit your public profile link on the right. This is a very important setting, as this controls if or how major search engines, such as Google, Bing or Yahoo! see, index and display your LinkedIn profile.
The best option is to prevent search engines' access to your LinkedIn profile - click the Make my public profile visible to no one option on the right side of the screen. This will avoid accidental leakages of your private data.
If you do want to appear in search results, select the Make my public profile visible to everyone option, but please limit the exposed data to Basics only!
Click Go back to Settings on the top right.
That's it for Profile settings.
LinkedIn Communications settings
Click the Communications tab. Then open Select the types of messages you're willing to receive.
You should limit the LinkedIn message types to Introductions and InMail only and deselect all categories in the Opportunities section. This will prevent careless or malicious people from spamming.
Type a descriptive text in the Advice to people who are contacting you field.
Click Save changes.
Open Select who can send you invitations next.
To prevent spamming, select the Only people who know your email address or appear in your "Imported Contacts" list option.
Remember to click Save changes!
On the right, in the LinkedIn Communications section, click the Turn on/off invitations to participate in research link. No, this option is not for scientific researches, but marketing. Yeah, the long questionnaires... 
Clear the Yes, I'd like to receive invitations to participate in online research studies check box and click Save changes.
Click Turn on/off partner InMail next. This controls LinkedIn partners' ability to send you promotional mails. You know - buy this, buy that, we are the best, you are special to us, etc.
Clear both check boxes here before clicking Save changes. You really do not need the informational and promotional messages from LinkedIn's marketing partners or hiring campaign partners.
And that's all for Communications preferences.
LinkedIn Groups, Companies & Applications settings
Click the Groups, Companies & Applications tab. Then open Turn on/off group invitations.
If you like to discover and join LinkedIn groups, leave the I am open to receiving group invitations check box selected. If not, clear it.
Click Save changes.
To control whether to display a message on your activity feed after you've joined a new group on LinkedIn, click Turn on/off notifications when joining groups.
Clear the Yes, publish an update to my network whenever I join a group that has these notifications enabled by the group owner check box if you want to keep such activity private.
Click Save changes.
Next, click the View your applications link in the Applications section.
Here you can see all authorized applications and external websites. Check if you really need these, and if not, select the unnecessary items and click Remove.
In the Privacy Controls section, click Turn on/off data sharing with 3rd party applications.
To prevent leaking your personal information to third-party apps, clear the Yes, share my data with third-party applications check box before clicking Save changes.
Click the Manage settings for LinkedIn plugins on third-party sites link.
To prevent LinkedIn from learning your browsing habits via plug-ins on web sites, clear the Yes, allow LinkedIn to receive information about my visits to pages that use LinkedIn plugins check box.
Also, please remember to sign out of LinkedIn after you've finished using it!
Click the Save changes button.
LinkedIn Account settings
Open Account tab. In the Privacy Controls section, click Manage Advertising Preferences.
Enhanced advertising means that you might see personal ads on LinkedIn partner web sites. For example, "Oh, you got a new job? Checking typical payroll... How about a new Ferrari?" 
Not that bad (hopefully), but you should not allow advertising companies to track you. So please clear the LinkedIn may show me ads on third-party websites check box and click Save changes.
In the Settings section, click Manage security settings.
As you see, here are the two most important LinkedIn settings - secure connection and two-step authentication.
First, tick the A secure connection will be used when you are browsing LinkedIn check box. This will ensure that all your sessions are fully encrypted using the HTTPS protocol.
Next, if you want to use two-factor authentication for signing in to LinkedIn, click the Turn On link.
This additional security feature means that you'll receive a six-digit security code on your mobile phone after you sign in from an unknown or new device, and you can access your account only after inputting the code. This will keep hackers away even after they steal your user name and password.
Web browsers must be configured so that they will not delete cookies stored by LinkedIn, otherwise you must enter a new security code each time you log in to your account.
You must then enter your mobile phone number that will be used for receiving verification codes. Your country is detected automatically, but you can change it if necessary. Click Send Code.
Type the verification code that arrived via SMS and then click Verify. You'll also receive an e-mail from LinkedIn to notify that you are now using 2-factor authentication.
That's it - your LinkedIn account is now much more secure!
If you get a new phone number later, just click the Change phone number link to set it as the mobile that receives the verification codes.
Here's an example of LinkedIn's Two-Step Verification. Input the 6-digit code from the SMS you received. If you are planning to use the browser or device for accessing your account frequently, tick the Recognize this device in the future check box. If not, clear it.
Then click Verify.
You will also receive a notification e-mail from LinkedIn about each login attempt from an unrecognized device.
In case you receive such e-mail and you have not tried signing in to your account, you should change your LinkedIn password immediately.
And here's how to change your LinkedIn password. Just click the Change password link on the Account tab.
Type your present password into Old password field. Then fill New password and Confirm new password fields and click the Change password button.
Remember to create a strong and unique passphrase! Never re-use passwords! Consider using free password manager software to store and auto-fill your user names and passwords securely. You can use free Trusteer Rapport to protect your online accounts.
