Yahoo! Search Support for 'NOYDIR' Meta Tags and Weather Update from the Yahoo Search Blog covers how at long last, you can now tell Yahoo to not use Yahoo Directory information to make a title and/or description for your web page listings. It also cover how Yahoo's currently doing a reindexing change that might impact rankings. More on that below, plus tips about also blocking the Open Directory information from being used for your pages and some possible conflicts with multiple robots tags.
Sometimes pages are listed in both Yahoo's crawler-based search results and within its human-compiled directory, the Yahoo Directory. In those cases, Yahoo usually replaces the title and description of a web page in the crawler-based results with the information from the Yahoo Directory. Yahoo has operated this way for as long as I can remember -- that's over a decade 🙂
Now this has changed. Sometimes a site owner might not want the Yahoo Directory description to be used for their page. A case in point is Tony Knowles. The Yahoo Directory lists him this way: