The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.
- Poetry (5 members)
- Politics (90 members)
- Ports (25 members)
- Potrock (1 member)
- Privacy (51 members)
- Programming (58 members)
- Programming Languages (33 members)
- Programs (87 members)
- Protocols (40 members)
- Psychology (80 members)
- Public domain images (18 members)
- Punk (13 members)
- Python (9 members)
- Quotes (12 members)
- Random (65 members)
- Reasons to boycott the music industry (9 members)
- Religion (89 members)
- Robert Anton Wilson (48 members)
- Routing (11 members)
- SSL (2 members)
- Satire (4 members)
- Science (99 members)
- Science Fiction (14 members)
- Scripts (35 members)
- Scripts (UNIX) (5 members)
- Searches (22 members)
- Second Life (2 members)
- Security (24 members)
- Select category (1 member)
- Seti (28 members)
- 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)