Digital resources Many schools choose to direct students acceptable and valid material, either through free proven resources or subscribing to Web-based references. Companies with a proven track record in education, such as National Geographic or Discovery, have revised their vast print and video archives for Web delivery. Many of these organizations now consider Web distribution important and develop materials and tools that capitalize on its unique attributes. Schools that use free resources must weigh the possibility that they may contain advertisements or that students may leave the environment for expanded Web surfing. Subscription services also provide valid resources and help to support student inquiry in a safe environment. More than electronic encyclopedias, subscription services include content in a variety of Web-based formats and many support dynamic content generation by teachers and students as they connect schools to others around the world. Free Digital resources AOL@school Ask Jeeves for Kids Discovery National Geographic Public Broadcasting Service (PBS) Researchpaper.com Subscription services Electric Library K12Planet LetterGrade PowerSchool