approaches:
- purchase groups (database, automation, many-to-many)
- customer reviews (many-to-many)
- the page you built (database, automation)
- recommendation lists (many-to-many)
- customers who bought that bought this (database, automation)
- internet movie database (database, automation)
- search inside the book (database, automation)
- auctions (live, many-to-many)
- wish lists (many-to-many)
- sales ranking (database, automation)
- resellers (many-to-many) [viral]
- listen to audio samples (multimedia)
- available in PDA version (location-independent, device-independent)
totals:
- All 6 web strengths
- exploit their database for more than just storing orders