three degrees of separation 
This explains the participation of Berlusconi to the eighteenth birthday Noemi (see photo). It 's the daughter of the driver of Craxi. So, it's just a matter of social networks: Berlusconi was "friend" of Craxi, Craxi had (at least) a driver, this driver has a daughter. Ergo, between Berlusconi and Naomi have three degrees of separation. But the question is: Berlusconi participate in the birthdays of all children (or children) of all drivers / butlers / Secretaries Craxi? Or, having a limited amount of time, choose to allocate only to someone who has some particular characteristic, as well as the short distance from him in the network?
This explains the participation of Berlusconi to the eighteenth birthday Noemi (see photo). It 's the daughter of the driver of Craxi. So, it's just a matter of social networks: Berlusconi was "friend" of Craxi, Craxi had (at least) a driver, this driver has a daughter. Ergo, between Berlusconi and Naomi have three degrees of separation. But the question is: Berlusconi participate in the birthdays of all children (or children) of all drivers / butlers / Secretaries Craxi? Or, having a limited amount of time, choose to allocate only to someone who has some particular characteristic, as well as the short distance from him in the network? 
