yum update was ineffective?

[Gerry Tool]

My RHN applet indicated there were 7 updates to be installed, so as 
root, I ran

yum update

It went through the paces, eventually downloading 10 packages after 
several mirror changes to get the total set.  It then presented me with 
the command line prompt.  Apparently it did not do an update, since RHN 
still indicated a need to update.  I ran up2date and it went through the 
normal process, downloading and installing the updates.  RHN applet is 
now blue again.

Previously I remember that after a yum update, the RHN applet would turn 
blue, and it it didn't, asking it to check for updates would satisfy it.

What happened?

Gerry