أنشئ حسابًا أو سجّل الدخول للانضمام إلى مجتمعك المهني.
I not sure but I think the hierarchical is for define the type of site such as : company, university, organization ... etc. and also to define the site country such as : sa, ue, sy...etc.
the iteration is to speed up the URL resolving to IP because there are a lot of DNS servers in the world.
