All answers could be summarized as "none of your business", but since some doesn't accept tl;dr…
Q: Why don't you use your face as profile photo?
A: Why should I? it's not like I have an interesting face, you know? If you really want to see my mug, there are three 2011 photos on g+ and a 2007 one around the net (I don't like being photographed)
Q: I'm in your circles but... Nothing "juicy" on limited posts?
A: Nope. And even if I've circled you, I have several "access rings" circles, so that I could choose who the post is visible.
Moreover, I discuss really private matters in real life, by phone or by DCC chat. In short, 1-1 channels.
Q: Why that nickname? (it's ozone89 or variants)
A: I liked how it sounded, and having had breathing issues at the time, it seemed ironical too.
Q: What's that silly avatar?
A: It's Colonel.EXE's NaviMark (read: symbol), a swordsman program from MegaMan Battle Network (wiki or Google images for more infos).
Update 13/12/2014: Current avatar is the Guild Of Maintainers crest from Uru
Q: Why do I see bogus character when you write something?
A: Oh, Lord... If is just one in the middle of a word, it's an accented vowel (è à ì and so on. Italian language has these. Be thankful I'm not Nordic); if it's a sequence it's probably CJK (read: Japanese). In both cases, I'm using UTF-8, while either your PC or your site (if I'm leaving a comment) is using 8859-1 or similar. Wake the FSCK up and change your charset, for $deity's sake! It's 2013, not the 90s!
Q: Uh? What was that $ word?
A: It's a bash-like variable. Consider it a way to train your guessing skills (or, in that case, a way to make any religion happy).
Q: I'm a recruiter, may I peep your profile on order to get what kind of person you are?
A: Less browsing, more CVs! Go back to work, you lazyass! And even if you do, good luck, I have different "attitude profiles" for everybody, how I behave in my private life is completely different from when I'm on the clock.
Oh! I fell much better now!
Nothing like a rant at 5:25am to relieve some stress!