The following categories exist on the wiki, and may or may not be unused. Also see wanted categories.

• AI‏‎ (8 members)
• Home‏‎ (3 members)
• Marketing‏‎ (17 members)
• Psychology‏‎ (1 member)
• Semantic Web‏‎ (1 member)
• Test‏‎ (0 members)