In order to capture data, you need to capture the audience’s attention.
A viral Flash game was designed as part of a wider Christmas campaign, in which presents were falling from the sky and the player had to make elves catch them before the time ran out. Very simple, very fun, and very good for data capture.
Because the game was so addictive, people shared it with their friends, especially online. Many then submitted their high scores, which required them to enter their email address. The result was a large amount of contact information being willingly supplied, all while having fun and being part of a festive shared online experience.