Today was the first official day of the full (3-day) conference, with about 2,200 full conference attendees. Officially, PASS claims there are 2,998 registrations from 46 countries, but that number includes pre- and post-con attendees (who are also attending the full conference), plus Microsoft employees.
As you might expect, the Seattle Convention Center was packed with DBAs all wearing their orange and brown lanyards with their attendee badge, many carrying bags of swag they picked up from the various vendors attending the conference.