Microsoft

Overview

Microsoft deploys several distinct tracking and analytics tools on third-party websites: Microsoft Clarity (session recording and heatmaps), the Universal Event Tracking (UET) tag for Microsoft Advertising conversion tracking, and the Bing Ads remarketing pixel. Each serves a different purpose but all fall under non-essential data collection requiring consent.

What This Script Does

Microsoft Clarity Clarity injects a recording script loaded from www.clarity.ms. It captures:

• Full mouse movement paths and click coordinates on every page
• Scroll depth and scroll velocity
• Rage clicks (rapid repeated clicking), dead clicks (clicking unlinked elements), and quick backs (immediate back navigation)
• Page content through DOM snapshots reconstructed into visual session replays in the Clarity dashboard
• Session metadata: session duration, pages visited, entry and exit pages
• Device type, browser, OS, viewport size, and language

Clarity sets the following cookies:

• _clck (first-party, 1 year) — unique visitor ID hashed with site ID
• _clsk (first-party, 24 hours) — session grouping identifier for clustering page views into sessions
• MR (third-party via c.clarity.ms, 1 week) — Microsoft-wide user identifier
• MUID (third-party via c.clarity.ms, 1 year) — Microsoft User ID used across Microsoft properties and Bing Ads

Clarity also uses localStorage for session identifiers. Session recordings and heatmap data are transmitted to www.clarity.ms and stored in Microsoft Azure.

UET (Universal Event Tracking) Tag The UET tag loads from bat.bing.com and fires conversion events when users complete actions on advertiser sites. It sets:

• _uetsid (first-party, 24 hours) — UET session identifier
• _uetvid (first-party, 1 year) — UET visitor identifier for cross-session tracking
• MR (third-party, 7 days) — Microsoft remarketing identifier
• MUID (third-party, 1 year) — Microsoft User ID for cross-property audience membership

The UET tag contacts bat.bing.com for conversion event logging and bat.r.msn.com for remarketing pixel fires. It collects page URL, referrer, event type, conversion value, product identifiers, and browser metadata. This data feeds Microsoft Advertising campaign reporting and enables retargeting on Bing Search and the Microsoft Audience Network (MSN, Outlook.com, LinkedIn).

Bing Remarketing Pixel A subset of UET tag functionality focused on audience building. Fires a tracking request from bat.bing.com to record page visits and construct retargeting lists. Sets the same MUID and MR cookies as the UET tag.

Consent & Compliance

GDPR/ePrivacy: Clarity's session recording captures behavioral data that constitutes personal data under GDPR. The UET tag and remarketing pixel perform advertising profiling and cross-site tracking. All require explicit opt-in consent under GDPR Article 7. The ePrivacy Directive requires consent for all non-essential cookies including _clck, _clsk, MUID, _uetsid, and _uetvid.

CCPA/CPRA: The UET tag and remarketing pixel share behavioral and conversion data with Microsoft for advertising purposes, qualifying as selling or sharing personal information. Opt-out via Global Privacy Control (GPC) signals must be honored.

EU-US Data Transfers: Microsoft participates in the EU-US Data Privacy Framework (DPF). Standard Contractual Clauses (SCCs) serve as an additional transfer safeguard.

IAB TCF: UET and remarketing pixels map to IAB TCF Purposes 1, 2, 3, 4, and 7.

Consent category: Analytics (Clarity) and Marketing (UET, Bing remarketing).

Should You Block This Without Consent?

Yes. Both Microsoft Clarity and the UET/remarketing scripts are non-essential. Clarity must be gated behind analytics consent; UET and the Bing remarketing pixel must be gated behind marketing consent. Block all Microsoft tracking scripts until the user has granted the applicable consent category.