What is Personas Merge Protection?

Personas merge protection algorithm protects your identity graph from unnecessary merges by finding and removing untrusted external IDs. Here's an example:

In this example, anonymous_id: a1 is not reset during a User Logout. Without merge protection, we'd merge user_id u1 and user_id u2. Instead, our Merge Protection algorithm detects that such a merge would break user_id uniqueness and prevents the merge.

This is especially helpful for preventing "blob users" that are merged together by non-unique anonymous IDs or by common group emails like team@company.com

If you have any questions or see anywhere we can improve our documentation, please let us know or kick off a conversation in the Segment Community!