Too bad their sample request url's do not work!

Their width of services is more than google - image, news and video search capability in addition to standard web search.

They seem to think that location based search is a separate category.

It does offer choice to web services based service providers. However for Yahoo I think it is a bit too late.

Yahoo! Search Web Services

BTW: I am fascinated by the rss feed capability provided by MSN search which I have been using for a couple of weeks now. It is an useful alternative to screen-scraping and satisfies some needs of web service users.
What is missing from MSN picture however is the basic access through web services. How many versions till they get it?