The NOYDIR is a tag you can use to tell Yahoo not to display your Yahoo Directory title in the Yahoo Search results. We have a few reports saying that Yahoo, all of a sudden, started showing the Yahoo Directory title for sites that have the NOYDIR tag on them.
Just this last few days Yahoo is ignoring this tag on my site:
<meta name="robots" content="noydir" />
And has reverted back to showing my Yahoo Directory title and description.
It is probably just a temporary bug.