The more engaged users are, the more features an application can
sustain. But most users have low commitment — especially to websites,
which must focus on simplicity, rather than features.

In designing any user interface, one of your key decisions concerns the tradeoff between features and simplicity. The more features, the more complicated the system inevitably becomes:

  • Features have to be shown to users, so screens get busier.
  • Menus get bigger and/or more numerous, making it harder for users to find the features they need.
  • Features must be explained, ballooning the size of the help system and/or the manual:
    • Fatter documentation takes longer to read and makes it harder for users to extract a good conceptual model of the system.
    • More docs also make it harder for users to find the explanations they need.
  • Each extra feature offers more rope for users to hang themselves: they’re more likely to use the wrong feature,
    either as an error of intent (a mistake caused when they think the
    wrong feature is the one they need) or as an error of execution (that
    is, a slip, as when they click the wrong button in a crowded toolbar).
    Conversely, Steve Jobs famously defended the Mac’s one-button mouse by
    pointing out that users would never click the wrong mouse button.
  • The number of feature interactions grows by
    the square of the number of features: more can go wrong, and it becomes
    harder for users to understand why a change in one corner of the system
    has an effect in another corner.
  • The more options users have to choose from, the more time
    it takes their brains to prepare for action and decide what to do. Even
    if a fancy feature can theoretically execute a task faster, overall
    system use often slows because users spend more time on the mental
    operations required to choose from among features than they save from
    the more efficient feature.

The answer seems clear: minimize features and chase simplicity at any cost. This is indeed the case for most user interface design, but not for all projects.

User Engagement Levels

Users’ willingness to learn
is the most important factor in how much complexity you can allow in
the user experience. If people are extremely excited about a user
interface, they’ll welcome more features and will spend the time to
figure them out.

Mostly, though, users have a low engagement level with user interfaces and just want them to get out of the way. People don’t want to spend time learning, they want to spend time doing — a well-documented effect called the paradox of the active user.
(It’s a paradox because people might save time in the long run if they
spent more time learning about powerful features. But, empirically,
users almost never want to do this, and you should design for how
people actually behave, not how you wish they behaved.)

Shallow Engagement with Websites

Where does your website fall on the 1-3 scale of user engagement we saw for Photoshop? Outside the scale,
at level 4. People don’t want to read 20 pages of instructions to use a
website. They demand instant gratification or they leave.

The user engagement level with websites is incredibly low, as dictated by information foraging: people don’t commit easily to any individual site, because it’s so easy to get to other sites. Skimming the cream from each site is usually the superior browsing strategy.

As studies in my recent book document, users visiting a new site spend an average of 30 seconds on the homepage and less than 2 minutes on the entire site before deciding to abandon it. (They spend a bit more time if they decide to stay on a site, but still only 4 minutes on average.)

Thus, websites should have almost no features: focus on the words.

To determine how much complexity you can afford in a user interface,
you must analyze user engagement levels: Do they care deeply, or do
they just want to get something done as quickly as possible? Typically,
users care less than you think! You’re not important to them. This is
one of the main reasons companies need systematic usability studies: to
make explicit the fact that outside customers don’t find your design as important as you do (because you work on it all year).