How to keep a guy you haven't met interested through email exchanges?

I'm 25. I recently found a childhood friend from facebook and we have been exchanging emails. So far, he responds to my e-mails but isn't asking much questions about me. I seem to be the one asking him questions. The only questions he asked were if i have been in contact with other elementary school friends. Does this mean he is only interested in a platonic friendship or it's too soon to know? How can I keep him interested that would make him want to meet me? What should i include or leave out in emails? Should i continue to ask him questions or not ask too many? Should I talk about myself when he doesn't ask?