So that Ajax nevermore shall they insult.
Although the line between web applications and web services is blurring, most web applications are built primarily for humans. Whether it's a weblog system for your eyes only, an internal time-tracking tool for a dozen people in your department, or the next social-networking phenomenon, a web application with no users is like a party with no guests: what's the point? Directly or indirectly, users are the whole point. So when it comes to designing your site, they shouldn't be an afterthought.
Users are the focus of this chapter: how they think, what they want from a web application, and how to help them get itin a word, usability. Usability is about getting out of the user's way and helping him work as effectively as possible. It's about building tools that are not just merely functional but actually pleasantdelightful evenand that work with the user.
Designing for usability is part science, part art. First, it draws on knowledge of how people think and behave by considering questions such as:
How much information can someone think about at once?
What words will be associated with a certain concept?
What reaction will some stimulus cause?
That information isn't enough on its own; it must be augmented with knowledge of the problem domain; for example:
What is the user ultimately trying to accomplish? Why? In what context?
What are the alternatives, trade-offs, and risks involved?
Those questionsof psychology and contextinform the science of usability design.
The art happens when that knowledge is synthesized into practice: balancing the forces of a problem into a workable design, choosing which elements to omit and which to emphasize. When it's done right, the solution fits the problem like a gloveit's just enough and no more.
In this chapter, we'll first examine usability principles that apply to all contexts, then stop to consider the unique constraints of the web context, and finally get specific about common web usability problems and solutions.