Searching Tags
• Even with tag expansion, searching tags is
challenging
• Tags are inherently noisy and incorrect
• Many items may not even be tagged!
• Typically easier to find popular items with
many tags than less popular items with few/
no tags
Tag Expansion
• Can overcome vocabulary mismatch problem by
expanding tag representation with external
knowledge
• Possible external sources
✤ Thesaurus
✤ Web search results
✤ Query logs
• After tags have been expanded, can use standard
retrieval models