## ADDED Requirements

### Requirement: Standard click tracking taxonomy
The system MUST define and follow a standard taxonomy for tracking user interactions (clicks) across the website.

The taxonomy MUST define:
- required event name(s)
- required event properties
- allowed values for categorical properties (where applicable)
- uniqueness rules for identifiers

#### Scenario: Adding a new tracked link
- **WHEN** a new link is added to any page/component
- **THEN** it is instrumented according to the taxonomy (required event name and required properties) without additional bespoke tracking code

### Requirement: Unique identifier for every clickable item
Every clickable item that is tracked MUST have a stable identifier (`target_id`) that is unique across the site (or unique within a documented namespace).

The identifier MUST be deterministic across builds for the same element and placement.

#### Scenario: Two links in different placements
- **WHEN** two links point to the same destination but appear in different placements
- **THEN** their `target_id` values are different so their clicks can be measured independently

### Requirement: Minimum required properties
Every tracked click event MUST include, at minimum:
- `target_id`
- `placement`

For links, the event MUST also include:
- `target_url` (or a stable target identifier that can be mapped to a URL)

#### Scenario: Tracking a content card click
- **WHEN** a user clicks a content card link
- **THEN** the emitted event includes `target_id`, `placement`, and `target_url`

### Requirement: No PII in event properties
The taxonomy MUST prohibit including personally identifiable information (PII) in event names or event properties.

#### Scenario: Tracking includes only categorical metadata
- **WHEN** tracking metadata is defined for a clickable item
- **THEN** it contains only categorical identifiers (ids, placements, domains) and does not include user-provided content