I saw an image on a social network saying that if your using a public computer do not use the one which has the following port on it as your data can be extracted out. Now I am wondering how can your personal data be extracted? Is this port for system sharing? Please help out. Thanks
What you have posted a picture of is a physical keyboard sniffer / keylogger (similar to this device). That small unit will intercept all key presses from the attached PS/2 keyboard, and store it in the device. At a later date, the person who placed the keylogger can then retrieve the unit, and know exactly what keys were pressed on the keyboard by everyone who used the computer.
Your personal data can be "extracted" because when the attacker is viewing the keylog, any usernames and passwords that you typed will show up in the keystream. All the attacker has to do is look for key-words (Facebook, Hotmail, etc...), and then determine your username/password combo from the resulting keys.