flowchart LR
    M[External metadata] --> Q[Importer and review boundary]
    Q --> C[(Media catalog)]
    U[User] --> W[Responsive web product]
    W --> V[Viewing-state services]
    V --> H[(Diary and history)]
    C --> R[Recommendations from existing data]
    H --> R
    H --> P[Privacy policy boundary]
    P --> F[Friends and social views]