In July Yahoo! launched their BOSS API, which enables you to “build your own search service”. Today, they’ve expanded the functionality of that API by adding a Key Terms feature. The technology used in Key Terms is the same used for Search Assist, which provides search suggestions and enables searchers to explore concepts related to the query.

Yahoo! says they’re adding this feature in response to developers’ requests for greater access to “deep infrastructure assets”. The Key Terms feature uses term frequency and positional and contextual heuristics to return ordered lists that describe a web page. Each result returned for a query includes associated metadata of up to 20 terms that describe that result.

In the blog post announcing the feature, Yahoo! uses a sample query of [obama] to illustrate that the first result, change.gov, includes key terms metadata such as Vice President-elect, President-elect, American, and lobbyists.

Yahoo!’s post explains that the feature can be applied in other ways than illustrated by Search Assist and that it can be used for semantic analysis, relevancy models, and to categorize similar documents. They note that Yahoo! developer Ted Drake used Key Terms to power the “related terms” feature of his food-related search engine tartin3.com.

Since the launch, Yahoo! has been showcasing uses for BOSS technology. Generally, these have been different visual representations of results and filtered results.

Last week, Microsoft Live Search launched a fuller-featured API, which also opens up access to their data. Search engines have an amazing amount of data and intelligence about the web and it’s a great trend that they’re beginning to make that available to developers as the foundation for innovative web applications.

Related Topics: Top News | Yahoo: APIs

About The Author: Vanessa Fox is a Contributing Editor at Search Engine Land. She shares her perspectives on how search impacts marketing, user experience, and web development at ninebyblue.com. Her book, Marketing in the Age of Google, provides a blueprint for incorporating search strategy into organizations of all levels. Follow her on Twitter at @vanessafox. See more articles by Vanessa Fox