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To communicate with other intelligent life a civilization has to develope some sort of technology. If again we consider the 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 form. $f_c = 1$  Putting these factors into the Drake equation we get   $N \approx \frac{2}{3} L \approx L$ L$. Note this is basically the same result that Frank Drake obtained in 1961! The difference is that this has been obtained only making assumptions on the factors $f_i$,$f_l$ and $f_c$, since the other terms in the equation are now established.  %\href{http://en.wikipedia.org/wiki/Fermi_paradox}{Fermi}  %\href{http://en.wikipedia.org/wiki/Rare_Earth_Hypothesis}{Rare Earth}