Broadcasting a message means that all processes in the world will receive it. This simplifies the broadcast function relative to the send function:

int MPI_Bcast( 
   void *buffer,  
   int count,  
   MPI_Datatype datatype, 
         int root,    
   MPI_Comm comm) 

The receiving processes would simply use a normal MPI_Recv function. All that the broadcast function does is optimize the sending of many messages using an algorithm that uses multiple network links simultaneously, instead of just one.