# Measurement tags & taxonomy – tag communication patterns

This doc describes **tag communication patterns** and how a **measurement tags & taxonomy** feature could fit into Blueprint: consistent naming and structure for events and parameters across cross-domain, data layer, attribution, and implementation.

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## 1. Tag communication patterns (four areas)

### 1. Cross-domain

- **Linker params** (`_gl`, etc.) for client ID across domains.
- **Server-side identifiers** (user ID, hashed email) across touchpoints.
- Blueprint already has cross-domain snippets and domain lists; taxonomy here = **consistent naming and structure for linker/ID params**.

### 2. Within-page

- **Data layer** (push / listen), GTM variables, local/session storage.
- Taxonomy = **event names + parameter shape** (e.g. `event`, `userId`, `campaignData`) so every tag speaks the same “language.”

### 3. Cross-campaign attribution

- UTM persistence, attribution windows, postback/Conversion APIs.
- Taxonomy = **shared naming for sources, parameters, and conversion events** so GA4, Facebook CAPI, etc. align.

### 4. Implementation patterns

- Tag sequencing, custom dimensions/parameters, CDPs as hub.
- Taxonomy = **one shared event/parameter structure** across GA4, Adobe, GTM, server-side.

**Summary:** “Tags and taxonomy” in this sense = a defined way to **name and structure events and parameters** so all these mechanisms (linker, data layer, UTM, postbacks, GTM, GA4, server-side) stay consistent and communicable.

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## 2. How this maps to Blueprint

Blueprint already touches several of these:

| Area           | Blueprint today                                              |
|----------------|---------------------------------------------------------------|
| Cross-domain   | Domains list, linker-style snippets                          |
| Data layer     | Framework events (and suggested params) = “what we push”     |
| Server-side    | Server-side snippets, Measurement Protocol                   |
| GTM            | Import/export, comparison                                     |

**What’s missing** is an **explicit measurement taxonomy** that:

- Defines **event and parameter naming** (and optionally prefixes).
- Can drive **guidance in the app** (e.g. “use this structure for cross-domain,” “use this for data layer”).
- Optionally **documents or enforces patterns** (linker vs server-side ID, UTM persistence, tag sequencing).

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## 3. The “three things” (summary)

1. **Cross-domain / cross-site tag communication** – linker, server-side IDs.
2. **Within-page tag communication** – data layer, variables, storage.
3. **Cross-campaign and implementation patterns** – UTM, attribution, sequencing, shared event/parameter taxonomy.

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## 4. Measurement tags & taxonomy feature in Blueprint

A **measurement tags & taxonomy** feature in Blueprint could be the layer that:

- **Names and categorises** these patterns (e.g. “Cross-domain – linker”, “Within-page – data layer”, “Attribution – UTM”).
- **Defines a shared event/parameter taxonomy** (and optional prefixes) that the framework, snippets, and docs all reference.
- **Surfaces this in the UI** so users design implementations around tag communication and a single, consistent measurement taxonomy.

### Going deeper

To go deeper, narrow to one slice first, for example:

- **Data layer event + parameter taxonomy**, or  
- **Cross-domain + server-side ID taxonomy**  

and sketch how it would look in Blueprint’s framework and UI.