How to use Google Analytics for cross-device tracking?

@maci 

To use Google Analytics for cross-device tracking, you can follow these steps:

1. Implement User-ID tracking: User-ID is a feature in Google Analytics that assigns a unique ID to each user, allowing you to track them across different devices. This requires some developer implementation to assign and store the User-ID for each user.
2. Set up the User-ID view: In your Google Analytics account, create a new View specifically for User-ID tracking. This will help you isolate and analyze cross-device data separately.
3. Enable User-ID in the tracking code: Modify your Google Analytics tracking code to include the User-ID feature. Use the ga('set', 'userId', 'USER_ID') method to pass the unique ID for each user.
4. Ensure consistent User-ID assignment: Whenever a user logs in or visits your website/app on a different device, make sure the User-ID is assigned consistently across all devices. This ensures accurate tracking of the same user.
5. Implement cross-domain tracking: If your website spans multiple domains, configure cross-domain tracking so that Google Analytics can recognize users navigating between these domains. This provides a more complete view of the user's journey across devices.
6. Analyze cross-device reports: Once you have implemented User-ID tracking and collected sufficient data, you can analyze the cross-device behavior of your users in the User-ID view. Google Analytics provides reports like "Device Overlap" and "Device Paths" to gain insights into how users interact with your website on different devices.

Remember to comply with privacy regulations and ensure your tracking methods align with your privacy policy and user consent requirements.