You can tag each request with arbitrary key-value maps and search over these later. For example, if you add a `x-subtrace-tags: user=foo, project=bar` header on the response, you can apply a `tags.user == "foo"` filter in the dashboard to see all requests across your entire infra from that user and only that user. Each request is pre-populated by default with tags like hostname, pod name, AWS/GCP location, etc.

It's like Honeycomb's wide events but even better because: (1) you can see whole request including the payload alongside the event fields, and (2) it's fully automatic and requires no code changes out of the box (you can incrementally add these tags when you find a need for each one instead of the huge upfront cost from instrumenting the hell out of your codebase).