I did this myself today. I started an email, full of agreement, with 'no'. 'No, I understand', I typed. Meaning, I guess, 'you think I don't understand, but, no, you're wrong, I do'. It's odd. I do it in conversation 'no, that's right'. 'no, yes'. I do it a lot.
It's not just me, apparently.
It's a great article, you should totally read it. No, totally.