Ask questions based on their profiles.
It was very hard for me to not want to answer someone who was like
"I see that you've read __________. What do you think of his theorem on...?"
"I caught the TNG reference. I'm more of a Wars fan, meself. I forgive you, though.
"
"Interesting that you subscribe to Utilitarianism. Would you describe yourself as a Peter Singer fan, or do you prefer Bentham?"
Maybe the third girl was new- I at least put up a short temporary one while I was writing my longer profile- I put a lot of thought into it, so it took a while before it was ready.
Curious: what has you worried about being "too personal"?
Did you get sexual? You never GO FULL SEXUAL IN THE FIRST MESSAGE! 
_________________
"Such is the Frailty
of the human Heart, that very few Men, who have no Property, have any Judgment of their own.
They talk and vote as they are directed by Some Man of Property, who has attached their Minds
to his Interest."