Well, those links that you sent, are saying basically the same as I explained.
Yum and up2date are NOT unrelated, they share some functionality (updating installed packages). Yum can do many more things, but the update functionality is similar to up2date.
After you update with YUM the rhnsd will identify that all the packages are up to date thus the Alert notifier will stop blinking.
Very few times, I have updated with YUM and noticed that the Alert notifier keeps blinking. I attribute it to the fact that an update has just been published to the rhn and it has not been replicated to the yum repositories. I update later and the notifier stops blinking.
So there you have it.
To update with yum run the following command as root:
Yum will actually tell you how many MB you will have to download.