Well, yes and no.... the basic idea is that reverbs and the like work on a mult (or portion of the signal) mixed back with the original (to taste). This essentially means the original signal is not changed, but only a portion of it is sent thru the effect and mixed back in.)
This is very different than in-line processors (like compressors) which need to work on the whole signal. Whole signal goes in, gets processed, and comes back out...
That being said, there is a technique to applying compression in order to lightly smooth out the peaks while still maintaining some of the original dynamics. For this you run the compressor via the FX sends. But this is not a typical configuration.
Bruce