Here is a quote that yegg made earlier in response to a similar question:
"There is no change in terms of privacy. We still don't collect or share personal information and auto-suggest does not impact that at all. We simply do not associate queries with personal information (e.g. IP addresses)."
posted by Mallart 4 years and 10 months ago Link

Hi Mallart, thank you for your reply.
I read that, but what I wanted would like to know is if these searches are "self-learning" so DDG can guess what you are searching for, after a few searches (e.g. Python programming language / snake).
posted by luckiboy 4 years and 10 months ago Link
I don't think so. To learn that they would have to associate queries with personal information.
posted by clel 4 years and 10 months ago Link