The feature is "opt-out" so you can turn it off, as long as you know about it. Here's what to do to:

• On your LinkedIn home page, click on your name in the upper right hand corner of the page.
  
• A drop down menu will appear with two options: settings and sign out. Choose settings.
  
• On the settings page, click on Account at the lower left of the page. The box adjacent to the Account option will display a number of choices organized into groups—Privacy Controls, Settings, Email & Password and Helpful Links.
  
• Under the Privacy Controls group, click Manage Social Advertising. That will display a box that allows you to turn off the advertising feature.