Applications Share Your Information
Generally they have access to your profile information that you've made public, and share activities with your friends and followers. It's not only about applications made available on Facebook, some websites use their own applications to connect with Facebook and share your activities.
For example, If you're on Pinterest, you can link to Facebook to share your Pinterest activity on Facebook and it will broadcast what you have been pinning. Hence, information being shared via applications can be useful.
Why Application Privacy Matters?
Applications share updates or send notifications, when you interact with the application or as predefined. Further, it takes your predefined privacy settings into account when sharing updates on your timeline. Hence they don't prompt and ask each time, whom you wanna share with. Wouldn't that be annoying if they did?
However, you have to review your privacy settings relate to applications and make sure they are set up for the right audience. Else, you may come across embarrassing situations where your friends find you have been spamming.
Can I Change Now?
Also, there are some applications that sticks to your default privacy settings and give you no control over changing the privacy settings.
Anyway, Facebook allows you to review and control your application privacy anytime. If you find an application is sharing your activity, but not with the right audience, still you can change it. Let's take a peek which applications sharing your information, and how to take control of the privacy settings.
6. Once after changing settings, click Close button to confirm.