You mean humans use twitter ?
What about Machine account, I have never really seen the point of Human to Human Twitter communications,
but as for machine to human, now that is useful, a couple of line of code and my door bell now tweets when it's rung, Once i add the camera to the pi, it will tweet an image of the button presser too.
When i was running large batches of data processing, the machine tweeted, Feed me when it had reached the end of it data..
very useful easy to implement and fits in your pocket !