Yahoo may no longer be a search engine superpower, but it definitely has some useful data to share
Yahoo has a Suggest API much like Google and Bing do and even though it has lost the search engine war, it still gets many millions of searches every day and therefore has some useful data to provide.
Use Yahoo keywords to generate ideas for new content
Our Yahoo Keyword Tool will find thousands of the long tail keywords based on Yahoo searches. These long tail keywords are an invaluable source of ideas for content generation and also help you speak the user's language in your content.
Filter and Prioritize Profitable Keywords
The Yahoo Keyword Tool's "Buyer Intent" tab lets you filter only those Yahoo keywords that indicate a user's interest in purchasing a product. This makes it easy for you to prioritize those keywords that can generate more revenue.