I read an article[0] on HN[1] recently — it talks about the different types of documentation. To quote it directly:
"Documentation needs to include and be structured around its four different functions: tutorials, how-to guides, explanation and technical reference. Each of them requires a distinct mode of writing. People working with software need these four different kinds of documentation at different times, in different circumstances - so software usually needs them all."
I agreed with its premise — I've found things that only have "story format" docs (i.e. explanation / how-to guides) to be really frustrating. On the other hand, if all that's available is a deep and highly particular technical reference, it's really difficult to get started sometimes.