At the end of the event participants submit to the organizers a list of who they would like to provide their contact information to.
Specific age range based on gender is a common restriction for events.
The time limit ensures that a participant will not be stuck with a boorish match for very long, and prevents participants from monopolizing one another's time.
On the other hand, a couple that decides they are incompatible early on will have to sit together for the duration of the round.
Hurrydate was acquired by Spark Networks (Jdate/Christian Mingle). The advantage of online speed dating is that users can go on dates from home as it can be done from any internet enabled computer.
Pre-Dating was acquired by Cupid.com, but eventually became independent again. The disadvantage is people do not actually meet one another.
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.