The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Sex (1 member)
- Social Software (10 members)
- Social software (1 member)
- Socialism (0 members)
- Sociology (8 members)
- Software (209 members)
- Solaris (24 members)
- Solaris 10 (5 members)
- Solaris Networking (7 members)
- Solaris Zones (2 members)
- Space (1 member)
- Spam (3 members)
- Standards (3 members)
- Stub (2 members)
- Stubs (0 members)
- Study Guides (13 members)
- Subgenius (1 member)
- Sufism (1 member)
- Suizid (1 member)
- Sun Hardware (1 member)