She probably doesn't have some goal or plan. She's probably just like: this guy seems like he's got his act together. And he's kind of interesting. What does he like, Linux? Hey, want to hang out and talk about Linux? Oh shit I got some work to do instead for a while. Whew that's done, hey let's chat for a while. Hey that was fun, let's do it again sometime.
You can sometimes tell when someone is interested by how they look at you and respond to the things you do.
Maybe. I could never tell. A lot of times they weren't sure themselves.