http://spywareitdaiuyfo2sqb5vsg7mek5cjabdr73luhnda57t2hyuzg7yyd.onion/articles/duckduckgo.html
Ultimately there isn't proof that DuckDuckGo is spyware- but a few reasons to suspect it of being spyware. Even though, it's worth noting that DuckDuckGo offers an onion domain ... so you don't need to trust it to use it as long as you access it through TOR.