Former presidents traditionally try to build their legacies by taking on charitable endeavors; Donald Trump is offering “personalized greetings” to supporters on his website. CNN’s Jim Acosta discusses with Trump biographer Michael D’Antonio, who says the move is an effort to expand his mailing list.Former presidents traditionally try to build their legacies by taking on charitable endeavors; Donald Trump is offering “personalized greetings” to supporters on his website. CNN’s Jim Acosta discusses with Trump biographer Michael D’Antonio, who says the move is an effort to expand his mailing list.