>>1
Ok, let me. But first off, I have to tell you this:
Don't just use those expressions except when you
are on 2ch or related boards such as wakaba.
If you use them on other message systems
available in Japanese, you will come across as very bad.
I myself wouldn't use DQN and (ry when I e-mail my friends.

So, DQN stands for Do-kyu-m in Japanese, which means
A, someone foolish, mad, or out of their minds
B, someone with no or little knowledge on the topic other
2ch people are talking about.
C, someone who is a bit too childish to communicate with
others.etc.
Well, it's a little abusive expression, but
most of us think it deserves nuisances.

As for (ry, it sometimes is nearlly equal to "Blah-Blah-Blah" in English.
When you don't want to say something straightforward,
you can use (ry ,especially at the end of your sentences.
But there's another usage. When you respond to someone
such as a DQN and you want to imply
that you put (ry instead of what you really want to
say because it's obviously too common and boring to every reader except the DQN, you can use (ry.
So you need to tell which (ry means.

Did I make sense to you?