It is not only useful on our platform. The entire instant answer engine is open source as well, and could be incorporated in any program. Additionally, much of our Instant Answers are freely accessible via our API: https://duckduckgo.com/api. These could be and are incorporated in other programs. We are looking for ways to expand access and make them more useful, and would appreciate any suggestions.

That said, there are many for-profit companies that create and maintain open source projects that are primarily used for them. While that may mean that many people aren't interested in developing for them, it doesn't mean everyone isn't. There are some people who want to improve their own search results. There are some people who just want to help a private alternative in search.

There are others who would like exposure on our search engine pages (for their APIs or via developer attribution). In fact, as we get a decent amount of traffic now, that exposure has real monetary value. We place Instant Answers above ads and links, and so the sources that are used for Instant Answers are monetarily benefiting through their inclusion in the ecosystem. In any case, there are many valid reasons why someone may want to develop on DuckDuckHack.