The Online Family answers:

Though you can install filters to block out certain web sites, the best defense against inappropriate online content is: communication. Talk with your teens to come to some mutual agreements about what is -- and isn't -- OK for them to view online. Let them know some of the dangers that exist: Like things you can post on the Internet can be found by future employers or colleges, or even get you kicked out of high school these days. Also, warn them not to set up in-person meetings with anyone they've met online. Next, have them show you around their favorite web sites so you can have a better idea of where they like to hang out online. Come up with a family policy for Internet usage and make it clear that you want them to have fun online, but they need to respect the rules. Even better, find some web sites that are not just for idle time but are inspiring or educational -- like web sites that encourage their offline passions, volunteering or teaching them about interesting topics. Or give them some helpful web chores, such as finding your family a great hotel for your vacation this year or researching a new car you're thinking of buying. Finally, put the computer in a public space so when you're home you can keep tabs on what they're viewing.