Now we know.
DuckDuckGo will continue to get results, and a few extra features like date filtering on results, from Yahoo by way of a custom integrations between each service. Here’s the text over on the Yahoo subdomain duckduckgo-owned-server.yahoo.net:
Essentially, DuckDuckGo gets to control the core components of the integration, which should allow them maintain their previous privacy commitments. I’m not sure if DuckDuckGo is the only service to get a deal like this, but their 335 million search queries last month probably didn’t hurt negotiations. If you read between the lines, Yahoo needed this more than DuckDuckGo did.