Thx! I've never paid for PR (yet), although I'm theoretically not opposed to it. My strategy to date has just been to be as open as possible, e.g. answer all interview and other requests ASAP, etc. I've also met a lot of great people this way.
Well its working! Developers love openness and developers seem to be the main focus of DDG at the moment from what I have seen. Very impressed with it, especially since I have always been interested in the search space myself as a hobby.
The hacker news crowd loves you (deservedly so!) and you are doing an awesome job with DuckDuckGo. Keep up the good work!