Not a lot - Unless something came up that necessitated a PM - Talking about a question or a bit of friendship developed - It could happen with either gender, As far as I am concerned GaG is not a dating site but a social site for making friends of both genders.
I think I have messaged 9 girls till today. I ask them about education. LOL. I don't know why I do such things. However, I have messaged one girl last week asking about mast*rbation question. She is friendly girl , so, I did !