@Asyn
Thanks for the link, but it does not really explain much.
It says
"Avast Browser Cleanup offers a list of approved and AVAST-tested new search providers" etc. etc.
So I gather that only five search engines are "approved and AVAST-tested": Yahoo ("recommended"), Bing, Blekko, Google, Wolfram Alpha.
That's all good and fine, but I would like to know: was DuckDuckGo tested?
If yes, did it not pass the test? Are there concerns?
If not, why not? DuckDuckGo is used by users who care about privacy, so I hope Avast tests it.
I also wonder: why is Yahoo "recommended" over Google and others? Is Yahoo really a superior choice? Or does it come down to commercial reasons?