Although many people first go to the Web for information, it is not always the best place for what you need.

Most information on the Web does not go through a review process.
Anyone can publish on the Web without passing the content through an editor. Pages might be written by an expert on the topic. However many pages are created by people who know very little about a topic. Some people deliberately spread false information, or might even be disgruntled consumers trying to put a company out of business.

Some information on the Web is not free.
Many Web pages are free to view, but some commercial sites will charge a fee to access their information. Some sites allow free access to a few pages but require you to pay to see the best information.

Information on the Web is not organized.
Some directory services, like Yahoo or the Google Directory, provide links to sites in subject lists. But there are too many Web pages for any single directory service to organize and index all of them.

Most information on the Web is not comprehensive.
Although the Web is huge, there is a lot of important information that is not on it. Not all useful, current information is digitized and put on the Web. Also much older but still important information has not yet been made available to be published on the Web.

Most information on the Web is not permanent.
Some well-maintained sites are updated with very current information, but other sites may become quickly dated or disappear altogether without any notice.