If you’re setting up a Standard/Managed account, the Parental Controls checkbox affords you the opportunity to shield your Mac—or its very young, very fearful, or very mischievous operator—from confusion and harm. This is a helpful feature to remember when you’re setting up accounts for students, young children, or easily intimidated adults. (This checkbox is available for Admin accounts, too, but turning it on produces a “Silly rabbit—this is for kids!” sort of message.)
You can specify how many hours a day each person is allowed to use the Mac, and declare certain hours (like sleeping hours) off-limits. You can specify exactly who your kids are allowed to communicate with via email (if they use Mail) and instant messaging (if they use Messages), what Web sites they can visit (if they use Safari), what programs they’re allowed to use, and even what words they can look up in the OS X Dictionary.
Here are all the ways you can keep your little Managed account holders shielded from the Internet—and themselves. For sanity’s sake, the following discussion refers to the Managed account holder as “your child.” But some of these controls—notably those in the System category—are equally useful for people of any age who feel overwhelmed by the Mac, are inclined to mess it up by not knowing what they’re doing, or are tempted to mess it up deliberately.