If you need a manual to figure out how to use software, online or on the desktop, it’s probably a sign that something is wrong.
Software with user interfaces should be intuitive on three different levels:
1. At a Glance: as much as possible, the layout of the page, main headers, and button titles, should in short order tell a user what the software is supposed to do.
2. Passive Contextual Helpers: from place holder text, to help text beside fields and other elements, option names; they should all be helpful in showing a user what to do next.
3. Active Suggest Helpers: Auto-completion suggestions are the top helpers in this area, and as things get more complex, into the areas of artificial intelligence – helps that show up, suggest, or change based on user input.
A standard principle of software interface design should be surface simplicity, and deeper layer exposure of complexity.
Things should be simple at first glance with the most common tools at first click, but the option should be there to add more complex filters and features; all organized in similar areas of functionality.
If the surface complexity is such that you need to read a documentation page to get started, then things need more abstraction.
Not everything can be one click, but a user should be able to start experiencing at least some small degree of usefulness with a minmum of selections and clicks.
Hiding complexity means more complexity inside the black box, but in the end everyone benifits, and it can force a more well thought out design, and better architected internal workings.