Yahoo! Adopts Site Maps (urllist.txt)
You can also provide the location of a text file containing a list of URLs,Yahoo!'s site map technology is far less complicated than Google's sitemap, which must be a special file formatted in XML. Although, unlike Yahoo!'s urllist.txt, which is purely a list of URLs. Google's sitemap.xml contains more information. Such as: last date modified, projected change frequency, and page importance.
one URL per line, say urllist.txt. We also recognize compressed versions of
the file, say urllist.gz.
While neither of these will probably increase your rankings, they will help ensure that every page you create at least has a chance to get "on the map".
Links: Yahoo! Search submission page, Google's Sitemap login page