I just spent half an hour trying to find a conclusive result in google using just the data I included in the post and couldn't. Can you say what queries you used to get to this guess? Were you completely unfamiliar with the matters I described before attempting the search? What did you assume while searching?
I'm not saying you're right (or wrong) but I'm really interested in the process.
I used the name half of the email address in your profile. From there, I looked through the places that had that username. None of them gave very much useful information until I came to http://www.racjonalista.pl/index.php/s,47/k,32138 . From there, I looked up what PL represented, and it's Poland.
Addendum: Also, Googling your HackerNews username, on my second page of Google shows more .pl domains where that username is found.
Nothing really scary here, I just didn't think of adding data from my profile to the queries :) It's stupid, because if it wasn't my profile and my post I would probably do it the same way. I tried to google the country using only the informations included in the post but I somehow forgot that I'm the author and the fact that I live here was in the post too. Oh well, it happens ;)
Thanks for explanation and for hinting to google results for my username - I haven't tried that one for too long.
Similar to sukuriant, I googled the name half of your email in your profile, clicked on your Trello profile, copy&pasted the text from your first entry (I did not recognize the language) into Google. Google Translate told me it was Polish.
Also, on your twitter account (same username as on Trello), you mention Warsaw a few times.
I was completely unfamiliar with the matters you mentioned in your comment.
Ok, this is getting scary - the twitter account I used exactly once during a hackathon a year ago (we were mining geolocation data from tweets...) and since completely forgot. I try to control my online presence but it seems that I need to get more serious with it unless I want such things to float around forever. Thanks for explanation :)
I'm not saying you're right (or wrong) but I'm really interested in the process.