Walk me through what happens technically when an anonymous visitor becomes a prospect.

The tracking code drops a first-party cookie and Account Engagement starts a visitor record, logging page views and referrer data even though nobody knows who the person is.

Conversion happens when the person performs an identifying action: submitting an Account Engagement form or landing page form, submitting a form handler, or clicking a tracked link in an Account Engagement email. At that point the email address is tied to the cookie, a prospect record is created (or matched to an existing one by email address), and the visitor's prior browsing history is attached to that prospect's activity timeline.

Two practical consequences: first, the retroactive history means a prospect can arrive with weeks of behaviour already visible, which matters for scoring. Second, because identity is cookie-bound, the same person on a different device is a different visitor until they identify themselves there too.