Sometimes called the grounded emitter, since the emitter capacitor connects the emitter to ground at ac frequencies.
Since, as far as ac is concerned, the emitter is joined to ground, both input and output are connected to the emitter.
Current gain is Ic/Ib and can be quite high, typically 50.
Voltage gain is high, typically 250.
Input impedance is medium, say 5K.
Output impedance is medium, say 20k.
The output is inverted with respect to the input. Its most common application
is as a voltage amplifier.