A handbook on web and mobile usability that anyone with a stake in digital products will benefit from reading. The most useful part for me was the concept of usability testing presented as a lightweight, low-cost and repeatable process.
Krug's Definition of Usability
Every question mark adds to our cognitive workload, distracting our attention from the task at hand. The distractions may be slight but they add up, especially if it’s something we do all the time like deciding what to click on.
Here’s the rule: If you can’t make something self-evident, you at least need to make it self-explanatory.
Fact 1: We don't read web pages. We scan them. — We focus on words and phrases that seem to match (a) the task at hand or (b) our current or ongoing personal interests and (c) the trigger words that are hardwired into our nervous systems (e.g. "Sex" or our own name).
Fact 2: We don't make optimal choices. We satisfice. — We choose the first reasonable option, a strategy known as satisficing.
Fact 3: We don't figure our how things work. We muddle through. — An inefficient and error-prone method.
It doesn’t matter how many times I have to click, as long as each click is a mindless, unambiguous choice.
Get rid of half the words on each page, then get rid of half of what’s left.
"Omit needless words. Vigorous writing is concise. A sentence should contain no unnecessary words, a paragraph no unnecessary sentences, for the same reason that a drawing should have no unnecessary lines and a machine no unnecessary parts." — William Strunk (see The Elements of Style).
Your objective should always be to eliminate instructions entirely by making everything self-explanatory, or as close to it as possible.
As a rule, the persistent navigation can accommodate only four or five Utilities—the ones users are likely to need most often.
Test for good web navigation — You should be able to answer any of these questions if on any page of the site:
As quickly and clearly as possible, the Home page needs to answer the four questions I have in my head when I enter a new site for the first time:
Then, the fifth question: Where do I start?
Designers enjoy pleasant visual experiences. And developers tend to like complexity. The result is that designers want to build sites that look great, and developers want to build sites with interesting, original, ingenious features.
Usability test — watching one person at a time try to use something (e.g. prototype, web site, sketches) to do typical tasks so you can detect and fix the things that confuse or frustrate them.
Recruit loosely — try to find users who reflect your audience, but don’t get hung up about it. Instead, loosen up your requirements and then make allowances for the differences between your participants and your audience.
Resist the impulse to add things. When it’s obvious in testing that users aren’t getting something, the team’s first reaction is usually to add something, like an explanation or some instructions. But very often the right solution is to take something (or some things) away that are obscuring the meaning, rather than adding yet another distraction.
Note that while people love to make comments about the appearance of sites—especially about whether they like the colours—almost no one is going to leave a site just because it doesn’t look great.
Know the main things that people want to do on your site and make them obvious and easy.
Unless you’re going to make a blanket decision that people with disabilities aren’t part of your audience, you really can’t say your site is usable unless it’s accessible.