Most visitors never fill a form on their first visit. If they've identified themselves on another site in the network, the identity network can recognise them, so their early visits join the right person.
When a contributing workspace identifies someone (form, order, call or identify()), their email, phone, name, company and address are stored with the device fingerprints of their browsers. Workspaces that receive matches then get fingerprint matches (live, and retroactively for visitors seen earlier) and enrichment of missing fields for people they already know by email or phone.