A computer is an electronic device that accepts and processes information mathematically or logically according to programmed instructions.  The results of this processing is displayed visually, printed on paper, played audibly, kept in electronic form for transfer to other computers, or used to control some other device or process.
Modern computers have become a universal tool, used in most occupations.  The Internet itself, including DMOZ, this Internet directory, is written on computers, stored on computers, presented by computers, and usually viewed on computers.  By that standard every DMOZ listed site could be listed under this category. but instead, this category contains listings of sites primarily about the use of Computers other than for a purpose fitting one of the other DMOZ top level categories.  Sites about artistic use of computers belong in Arts, about scientific use of computers in Science, etc.
The ODP Computers category contains sites that are about:

• Computers in themselves in general, such as Computer History or Ethics or Computer Science;
• Specific individual parts and areas of all or most computers, such as Hardware or Software, not primarily used for or by a single DMOZ top level category field;
• The use of computers for purposes spanning multiple DMOZ top level category fields, such as Graphics, when the graphics could be scientific or artistic or business oriented, or for databases or the Internet in general, which store or carry all sorts of information, for whatever purpose;
• Fields that are only conceptually possible through the use of computer concepts, such as Artificial Intelligence or Artificial Life.

It is important not to confuse the topic with the tool or medium.  Websites devoted to a subject that happens to use computers as tools or a medium should still be listed under the subject.  For example, sites devoted to music, even in electronic formats, have a home in Arts/Music/.  However, the tools and formats for audio reproduction may also be used for speeches or lectures that are not Arts related, so sites devoted to these generic computer audio tools, data formats, theories, and algorithms that may be used for several purposes should be listed in the appropriate Computers subcategory.