LinkedIn have rolled out a new line of advertisements in which their customers' faces are used to advertise their sponsors' products. Helpfully, LinkedIn have decided to opt all their users into this. Here's a guide to keeping yourself from being an unpaid shill by opting out again.
1. Click on your name on your LinkedIn homepage (upper right corner). On the drop-down menu, select “Settings”.

2. From the “Settings” page, select “Account*”.

3. In the column next to “Account”, click “Manage Social Advertising” .

4. De-select the box next to “LinkedIn may use my name, photo in social advertising” .

A Box You Want to Uncheck on LinkedIn (via Making Light)