Good question... I've often wondered if it produces a shape of land rather than a style or formation of it. One time I played a Fractal map and it turned out to have regular land but a land shape in a giant zig-zag pattern and seemed extremely unrealistic. I cannot answer your question, but I'd like to chip in that it seems like it only generates a "random" shape of a map rather than the tectonics or aridity, food level etc...
Fractal sometimes gives really interesting (not the same as realistic) maps. I just played a game with Carthage on a map with two continents, one of them was a quite normal one and the one I was on was a huge double continent connected by a narrow land bridge like Americas. Probably the first time I found fort canals very useful.