A web site is an individual's or corporation's place on the web. If you think of the web as one global library and each site as an individual book, you will have a basic understanding of the web's organization. Newsgroups are more public general discussion areas that allow for threaded discussions. Mailing lists and newsgroups are topic-oriented, i.e., organized according to specific subject areas. Consequently, several professionals find that newsgroups attract too many irrelevant discussions to be worth their time.
Mailing lists are more popular among professionals.
Similar to a library's card catalog, a search engine provides a complete index of everything it has found. More intelligent and controlled search engines will be available shortly, which may improve their usefulness. Alta Vista, Lycos and OpenText Index are examples of some popular search engines. Because of this editing, guides tend to offer more useful and organized information. Mental Health Net is one of the largest such guides for mental health, psychiatric and psychological information.