It's a status game based on the day and month you were born. There's a list of 12 countries and each one corresponds to a month. You pick the country that matches the month you were born in.
The statement you then post is something like 'I'm moving to [country] for [date of your birthday] months'.
The rather stupid idea is that women all playing this game suggests that they are standing together in the fight against breast cancer!
My FB hasn't got that one yes I know a friend said a few months ago she was going to Germany for 2 years but even her husband wrote on her status confirming it