We talk online. But not in person?

So I've been talking with him on Facebook, and we have long conversations… On a Saturday night we even talked till it was like 2:30 in the morning!
Well, when we head back to school, we don't even talk in person… I always see him in the mornings at breakfast, and always walk right past him, giving each other eye contact, when I'm heading to 4th period…
I was about to say something to him, but I was too shy, because he is always with a group of people sometimes, or sometimes he is with his buddy…

(I'm the who sometimes start the conversations and sometimes he does too on Facebook)

Our conversations is about Minecraft, Zelda, and anime. (Stuff we have in common)
Well, I'm just wondering why he only talks online but not in person? Do I have to start the conversations?

Ofcourse its because of others around.
If you two were in one room with not a single person around you both will talk just like online