## 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.

The taxonomy MUST define namespaces for repeated UI surfaces. For the blog surface, the following namespaces MUST be used:
- `blog.subnav.*` for secondary navigation links
- `blog.card.post.<slug>` for blog post cards
- `blog.pages.link.<slug>` for blog page listing links
- `blog.post.*` / `blog.page.*` for detail page chrome links (e.g., back links)

#### 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)

For content-related links (clickables representing a specific piece of content), the event MUST also include:
- `title` (human-readable content title)
- `type` (content type identifier)

The `type` value MUST be one of:
- `video`
- `podcast_episode`
- `blog_post`
- `blog_page`

#### 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`

#### Scenario: Tracking a content link includes title and type
- **WHEN** a user clicks a content-related link that represents a specific content item
- **THEN** the emitted event includes `target_id`, `placement`, `target_url`, `title`, and `type`

### 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