I've posted a fair bit about protecting your online privacy, but most of it's only applicable to PC users. However, Mac users have an array of privacy self-defense tools at their disposal as well. First, go here and follow Lifehacker's instructions on configuring OS X to maximize your privacy (it's not at the top of the screen--you'll have to scroll down a bit to find the instructions. They're under the heading "Audit OS X's System Settings." For iPhone and iPad users: there's a free app called MyPermissions that will scan your online accounts and devices to see who's accessing your personal information. MyPermissions also sends alerts whenever applications gain access to your private information: you can immediately confirm or revoke permission for access. For completely secure and private phone calls and texts, download the app Signal. It's available for iPhones and Android phones. If you've got any doubts about Signal's security, don't take my word for it, take Edward Snowden's. For more tips and suggestions on being secure using your Mac devices, go here to the Mac Security Blog.