Am I flirting? Need Opinions Please.?

[SSike]

So, I was engaged in some friendly banter with a girl on twitter recently, (I tweet a lot, not just girls, but this one caught the attention of my wife because of the length of conversation) and my wife wanted to look at it, to which I happily obliged, thinking that there was nothing sinister in the conversations that I had. She saw a passage of writing that led her to think I was flirting with this girl, and I strongly disagree with her, so now I'm asking if people could tell me what their opinion is with the following dialogue:

HER: "And just as a matter of clarification: I use sarcasm when I want to be nice. Is that a contradiction in terms?"

ME: "Not a contradiction. Like the boy at school who is meanest to the girl he likes. Now just to figure out when you're sarcastic"

My wife says I'm flirting, but I felt I was merely making a comment analogous to hers about contradictions, and that was the first thing I could come up with. My wife however, thinks that I was subtly saying that I liked her.

Someone please help. I'm willing to admit I am wrong if I am, but I just don't see it.
@Chattu - Thank you for your reply. That definitely helps to hear this coming from another girl. I guess the important thing is to make sure she knows exactly how I feel about her, then talking to other people won't be so bad.
@Ron - I appreciate the insight. I think it's not so much that she thinks I am flirting with others, but that she thinks that those other people will think I'm flirting with them, and that results in her feeling foolish/disrespected.

[Shattu Satts]

Well.. in my opinion I don't think that your flirting with her.Your wife maybe mistaken because most of us girls usually doubt people and it's not easy for them to believe what the other person is doing.You you just need to take most of your time with your wife and express your love for her.Other than Twitter which your really fond of! Hope I helped!

[Ron]

I suggest you should figure out why your wife even thinks you are / have been flirting with someone else. Clearly her mind makes something out of nothing here. There must be a reason for her to be suspicious. It seems to me you have no intention at all to be unfaithfull, but your wife seems to think differently. Talk to her, ask her what she thinks has recently changed in your relationship with her. A happy wife wouldn't even think her husband is interested in other women, (even if he actually is, but that's another subject).