I actually still have the email.

Here's what I sent:

    Hello! 

    I don't have a lot to say to you, but I just wanted to say that about a month ago, I started the transition away from Google, and the most obvious thing to switch was search.  

    DuckDuckGo has improved substantially since the last time I used it (around 2012), and it's to a point where the results are comparable, and sometimes even better than Google, so changing was pretty seamless. Now the only Google-thing I need to remove from my life is YouTube. 

    As a somewhat technical person, I was curious about one thing; I saw that the primary language for DuckDuckGo is Perl.  Without making any judgement here, was there a particular reason for that choice?  Also, are you planning to move to Perl 6? 

    Anyway, I appreciate you reading my email.  DuckDuckGo is a great service, and I hope you guys keep up the good work!

    -Thomas Gebert. 

Here was his response:

    Yes, though, the primary language is Perl. It was out of convenience and interest since that was my primary language when I started the project. There was/are a lot of libraries useful for text processing / web crawling. Now Python and other libraries have been similarly built up.