This paper evaluates the quality of two major types of Web resources for K-12 education --information for research, and interactive applications for teaching and learning. It discusses an evaluation on the quality of 1,025 pieces of Web information (articles, research reports, news, and statistics) and 900 Web applications (tutorials, drills, games, and tests) used by K-12 teachers and students over a six-year period from 1998 to 2004. Findings suggest that (a) quality differs among information from different Web domains (.com, .org, .edu, and .gov); (b) quality differs among applications by different designers (professional designers, college students, K-12 teachers, and university professors); and (c) the quality of aWeb-based learning application influences a student's using and learning with it. Challenges and potentials of using the two types of Web resources to improve learning are discussed. A design-quality model is developed and tested.