"Facebook had a really boring deactivation page when you close your account... [One of the designers created a page] which has all your friends waving good-bye to you as you deactivate. Give you that final tug of the heart before you leave. This reduced the deactivation rate by 7%."
While that's a nice reduction in deactivations, it also strikes me as somewhat manipulative. It feels like many of the "social" companies see users solely as metrics to optimize, not as human beings.