What does it mean when a guy says "lol" a lot?

[725]

I am going to make this brief and not get into details. Basically, I like this guy and we just started talking on Facebook (he started the conversation with me!). However, he has a girlfriend (only of a month), so I am just trying to be friendly at this point. We talk a lot in person, but only just started talking on Facebook two days ago. We actually have a lot in common. We're both 19, but I'm not experienced with boys at all, and he's only had two girlfriends.
Anyway,
It's a mix between who starts the conversations. However, usually they're not on-going. For example, he might say something at 3:00, then I'll respond at 4:00, we'll talk for a bit, then he'll respond a few hours later. They're sporadic throughout the day.
He always responds to me. His favorite thing to "end" a conversation seems to be "Ha okay". He doesn't use any smileys or anything, but he always says the last word. He seems really flat on FB, which is the opposite of him in real life. I like to use smileys (not overuse them) to add more life and animation to my conversations. My friend said that a lot of boys just type flatly for no particular reason.
To get to my real question, he says "lol" a BUNCH in our chats. Not just "lol." He'll say something with it, but I just get the feeling that he's really bored. Could this be it? Is he bored? He thinks I'm funny, but, as I said, our FB conversations are very different from our real life ones. Does he just have nothing to say? Thanks