Web Ask a Librarian Journal Holdings Subject Trees Subject Trees, also known as directories, organize Web sites in some sort of subject order. They cover fewer resources but provide more focus and guidance on the topics they cover.
Subject guides involve some level of human intervention.
The best sites have subject experts who select high quality Web sites. Librarian's Index to the Internet - High quality sites thanks to expert, librarian selectors. Yahoo - The classic. Too general for browsing most academic research topics. It is good for news, financial profiles, and looking for known entities like organizations.