Those who wanted the giveaway had to agree not to join the new Facebook page, receiving their voucher for a Big Mac plus a signed goodbye letter from Burger King in exchange.
About 1,000 accepted the vouchers but even more left.
Burger King lost 30,000 followers as a result, but says its new fan base of 8,000 are more engaged and interact with the brand in a more positive way.
Losing 29,000 to get rid of 1,000 may seem like a steep price to pay. Perhaps the 8,000 remaining are more likely to post something positive which will show up in all of their friends' news feeds. If the 29,000 who left without the voucher were not "engaged," perhaps there was no ongoing flow of posts in their friends' news feeds to lose.