Apparently what guys are doing if they flirt with a girl that doesn't like them.

The act of seeking a hot person out in any means possible. Stalking is meant to be innocent and doesn't always make the person a stalker.

when no just isn't enough

How to show that you really love her

To consistently, persistently, and usually annoyingly follow someone around when you shouldn't be. Usually a result of
a) having too much time on your hands
b) having an unhealthy obsession/fascination with whatever you're stalking

Or what a lion does to its unsuspecting dinner when it's not sleeping in the mighty jungle.

When you freakishly obsess over a specific person and you get pissed off at anyone who claims him for theirselves. Especially Nicole Roberts who used to obsess over this kid named Sean.

Photographing people or people's houses without them knowing, then posting the photos on Facebook and tagging them as that friend.

More specifically, one can stalk while in a public setting, like in school or amongst friends, typically by pretending to text on a cameraphone, but actually taking a close-up and often unflattering photo of the person. This is best done with the camera feature on a Blackberry device.

Stalking can also be the practice of driving around (in cases of severe boredom) to various friends houses, awkwardly taking a picture of their house, then posting and tagging the photo on Facebook. This is an effective way of creeping out your friends, killing time, and wasting gas. Nonetheless, it is awesome, and credit should be given to the creator of stalking: Devina Parmar.