@andme:
http://127.0.0.1:8989/ncc/web/sigma-graph/nemgraph.html
("127.0.0.1" could be something else for you, if you are running NCC not at localhost but on a different machine.)
jabo38s is right: Yellow means that the nodes are not accessible from outside. Mostlikely the reason is a closed port (can ususally be opened through the web interface of the router).
0.4.28 is running pretty well for me. No crashes since 12 hours.
I asked cause of this (clicking up the node):
[img width=800 height=383]http://s23.postimg.org/uwevocvdn/Nem_Net_Work.png[/img]
branch already gone!! Block height more than 36557 :D
@Jabo: Thssnks for explanation