Unlike most print resources such as magazines and journals that go through an filtering process (e.g. editing, peering review), information in world Wide Web and Internet is mostly unfiltered. Using and citing information found over Web may not be reliable or authoritative. Therefore it is necessary to develop skills to evaluate what we found on the net. Fifteen evaluation documents for WWW are collected, analyzed from digital sources of U. S. academic libraries and common criteria for evaluating WWW resources are developed. Also several practical steps were made to overcome the quality problems.