What are Dim, Modifier and Sub ( ) vs Private Sub ( )?

I have seen the following macro name;

"Public Sub Initialize(ByVal Number As String, ByVal name As String, ByVal Importance As String, ByVal Estimation As String, _
ByVal Note As String, ByVal HowToDemo As String, ByVal Complete As String)"

Is this some new gener?
Also, I have learned that a macro name can't contain spaces, but above is working fine. How?