By default your FaceBook account allows your profile and picture to be used in advertising by friends or businesses. Though many times this could be a harmless thing if advertising for something like candy or a cause. If your face were to be used for a dating service your significant other or spouse might be a bit peeved.
This is the way to opt out of this option.
1. Go to Settings
2. On your settings page go to Privacy and click on the “manage” link.
3. Click on “News Feed and Wall”. On the next page click on the “Facebook Ads” tab.
4. Click on the small arrow next to “Only my friends” and you’ll see a drop down and here you can choose “No one”. After you made your choice click “Save changes” and your done.
This should help save you from any embarrassing moments and protect your privacy too. Have a great day!