You need to look at how many interactions are going like this. Internet game is kinda just like that. When you are face to face you have most of the girls attention, when your texting her or messaging on a site, you get her attention when she chooses to give it to you. The girl might not be interested at all and is just giving short answers rather than just ignoring you.
If it's a few girls, maybe just move on and focus on girls giving you good reactions and conversing, or try some outrageous crap that gets the girls full attention and just see what works.
In general if I feel like she's on autoreply mode giving short replies I'll say something like "wow we wouldn't get along very well, I like girls that talk more. Otherwise I'll never shut up. Oh well, thats too bad, you are a cutie
"
Sometimes that lets the girl know that I expect more of her and it helps her along to being more involved, sometimes it ends the conversation, lol.