I feel compelled to echo A.B. Carracho's sentiments directed to this application's developer: "Bless you."
I use this application frequently because it is a God send.
It has saved me tons of time when working cross-platform, particularly when I am working on a Linux box.
The great part about it is once you split the dfont file, you can pull just the specific form of the font you intend to use and leave the rest behind.
For instance, I am a heavy user of the Helvetica Neue font, but only in it's ultralight form. So I used dfontSplitter to extract all the different forms of the font on my Mac and then just took the extracted Ultra Light TTF file for upload to my Linux box.
And it's much easier to use this utility than it is to expend time searching for (and maybe not ever finding) a non-dfont file containing the font you need to use on a non-OS X platform.