I checked on Google, and it said it was a computer-type thing.
But on a quiz it asks:

Pick someone to do PDA in front of:
1. My friends, so they can see how lucky I am.
2. My ex, so they can see that I've moved on.
3. Anyone who's around.

4. No one, ew.

I didnt understand how that could be a computer. Can you help me? I dont know what it is!