Hi Carl,
Lets me try to explain in simple terms.
Seeing each other and forming neighbors and adjancies are different story all together.
On braodcast media the neighbor and adjancies is established between router interfaces who are in same subnet only and once formed then interfaces on different subnets are propagated to different routers via LSAs and all subnets see each other if those interfaces are included in ospf process.
HTH, if yes please rate the post.
Ankur