I just noticed that there have been only 983 downloads of SFK156, as of Saturday, March 13, 2010.

Why is such a powerful, excellent, wonderful tool used so little? What limits the popularity of SFK?

I think the quirky command line syntax is the biggest reason. The poor explanation of the quirkiness is the second reason.

It often takes 20 minutes or more to get SFK to work. The examples usually consider very limited cases, and are not explained well.

The 4 variations of MD5 utilities are an example. See at the bottom. The obvious use,
sfk md5 *.*
gives an error message.

This example works, but only if you want to put the MD5 hashes in a file:
sfk md5gento sfktest.txt -file *.*

   sfk md5gento=outfile dir   
   sfk md5gento outfile -dir dir1 dir2 -file mask1 mask2 !mask3
       create list of md5 checksums over all files.
          sfk md5gento=md5.dat .
   sfk md5check infile 
       verify list of md5 checksums. to speed up verifys by spot checking,
       specify -skip=n: after every checked file, n files will be skipped.
          sfk md5check md5.dat
   sfk md5   filename
       create md5 of file(s), without a list. "sfk md5" for details.