Less than a week ago, I wrote about LivingSocial's meteoric rise up Facebook:

Last week of March: 2,000,000 users End of March: 10,000,000 users First week of April: 14,500,000 users In the last six days, LivingSocial added another 5,500,000 million active users and is over 20 million. Remarkable growth - after all, that is 10% of Facebook's user base. It also shows the power of network effects:

livingsocial facebook app