Requirement for each event vary with the organizer.
Men and women are rotated to meet each other over a series of short "dates" usually lasting from three to eight minutes depending on the organization running the event.
At the end of each interval, the organizer rings a bell, clinks a glass, or blows a whistle to signal the participants to move on to the next date.
Speed Dating, as a single word, is a registered trademark of Aish Ha Torah.
Speed dating, as two separate words, is often used as a generic term for similar events.
As reported by the BBC in the Science of Love, it only takes between 90 seconds to 4 minutes of face-to-face interaction to determine attraction, which gives speed dating an advantage over online dating.