Why would he contact me after all this time...?

I was on msn now and I put a picture of Christian Bale as my msn picture. My ex boyfriend coincidentally also had a pic of Christain Bale as his msn pic. Now he knows that I love this actor and he said hi to me on msn. We haven't spoken in like 4 months and he was the one who ended our relationship. He use to say hi to me on msn but he stopped and it's been months since we've talked so I was really shocked when he said hi to me. The first he said was to bring up the Christian Bale coincidence then he strated to get nosy and ask me tons of questions especially having to do with graduate school. It's my last year of university and I put "applications" as my msn quote so maybe he figured I was applying. Why did he say hi to me after all this time? Was he just curious or does he miss me? Can I read into this at all or is it nothing?