The latter is actually really useful, not so much from the end-user’s point of view because I dare say they’ll never read it, but I always like writing documentation before coding. It makes the goal so much more clear in my mind, and then the coding is much easier. With agreed-upon documentation, writing tests is easier; with tests written, writing the code is easier.
Time for a beer — and I’ll drink to DFD (document first development)! Oh, and semantic linebreaks are great.