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To communicate with other intelligent life, a civilization has to develop some sort of technology. If again we consider Earth's case, this happened for humans but not, for example, for dolphins. The factor \textbf{$f_c$ measures the fraction of civilizations that develop communicative technology}. As intelligence and curiosity seem to go hand-in-hand, it seems conceivable that all intelligent lifeforms might eventually evolve towards a technological, communicative form. $f_c = 1$  Putting these factors into the Drake equation above  we get $N \approx \, \frac{1}{4}\, f_i \, L $.   This states that the number of communicative civilizations in our Galaxy is just the product of the chance of emergence of intelligent life times the average lifetime of a civilization's communicative phase. In the next and last post of this series I will show how the current search for radio signals from extraterrestrial intelligence has put some important constrains on the two factors $f_i$ and $L$, and how these informations can be used to make some bold predictions about the future of humankind.