By Frank Spillers

user alarm clock phone
Summary: Killer features are generally understood to be ranked highly on value proposition for users. However, there is a class of features that run under the radar of most sites, apps and experiences. These are features that bring users back, often without their conscious knowledge. They might even seem insignificant, but they provide some value that makes re-visiting worthwhile. Finding these features is an extremely worthwhile pursuit for product managers. 

Identifying hidden "killer features"

A "killer feature" is a concept software developers use to describe a high value or money-making aspect of a site, app or experience. Typically, these are either a) identified by experienced UX teams in advance of launch, or b) discovered or appreciated by customers as evidenced through sales, engagement or adoption. 

Many times, product managers and engineering teams have no idea why users adopt or like a feature. This is a common point of amusement in development teams: what a company thinks is the "killer feature" turns out to be something else according to the users of the site, app or experience. 

Two examples of reasons people find a product useful that had nothing to do with its core value proposition.

Example 1: The Facebook Birthday reminder. In a recent study of social media users conducted by Experience Dynamics, birthday reminders and birthday alerts were cited as a reason to keep visiting Facebook. Many users said they wanted to get off Facebook. Facebook's long-term user adoption strategy can be summarized by two elements: Email Notifications and Birthdays. 

facebook birthday reminders

2) Example 2: The Nokia alarm clock. Stay with me here, if you have never seen one of these. For a decade or more, Nokia was a dominant handset manufacturer globally (e.g. it was still 61% of the market in Africa in 2011). The top feature used according to Nokia users globally, was the alarm clock. Knowing this, you have to wonder why alarm clocks are so primitive on iOS? (Android offers a little more sophisticated alarm functionality). 

nokia flip phone

More killers feature examples:

  • SnapChat's dissapearing message feature has come to define the app's usage as well as acting as a privacy filter for teens who don't want parents monitoring their conversations (according to our users). This engages users at a deep level because it ties to a social need. 
  • Amazon's Wish List feature. Amazon has had this feature since its inception. For years, I kept Amazon wish lists and used them as a virtual bookshelf (and purchased many from the Wish List over the years). The feature, like all hidden killer features seems silly, and many ecommerce sites did NOT have it until it became standard.
  • Fitbit dashboard shows % to goal completion with clear playful infographics (as well as emails with a similar motivational reinforcement). These simple but clear infographics helped users quickly interpret data. They have become the standard is health and wellness apps. If you don't think these are important, compare these Fitbit to another fitness app. BELOW: Which one seems more motivating? For this reason, Fitbit's Visual Design seems like a hidden killer feature of their user experience adoption. 

fitbit vs other app- ux

Clues to finding hidden killer features

Look for social, emotional and temporal effects. Let's break these down:

  • Social: Aspects of your UX that provide social benefits. This can include privacy, as in the above example but might include reputation status (e.g. AirBnB Superhosts confer more trust). We are tracking at least 10 research based social UX effects we will share in a future post. Anything that bounces off the social interactions users have or that impacts their social presence, identity or life (as in the birthday reminder example).  
  • Emotional: Aspects of your UX that provide emotional benefits. This can include alleviating direct or indirect pain-points, for example Waze is a traffic mapping way, that offers Report a Police presence. Users can see if a cop is on the road ahead and adjust speed- if you happen to be speeding. This is more helpful than the rest of the data the app is based upon. 
  • Temporal: Aspects of your UX that provide time-based benefit. This can include time-based reminders or prompts as in a countdown timer (to an event) or on a ticket sale (customer conversion-related motivator). It might provide helpful or motivating prompts like "days left to process IPO application" like we found with workers at the Financial Industry Regulatory Authority who process applications. Note: users had a hand-written note taped above their desks as the reminder-- we later added it to the web app UX design strategy.  

Teams conducting regular deep user research (Ethnography, not user testing) ought to be stumbling across these hidden killer features in the user's natural environment. We regularly find these, and the source behind them. Ethnography is the user research technique that helps intercept current habits, current behavior and social or cultural effects influencing those habits or behaviors. In Ethnographic field studies, we look for social, emotional and temporal clues-- many of them rich with artifacts that can enhance or differentiate a design... or act as a hidden killer feature that propels user adoption. 

Based on our experience, it is difficult to find hidden killer features from inside your company or organization. Sometimes a start-up will be based solely upon that feature or MVP (minimum viable product). However, most start-ups as well as Enterprise organizations are infamous for defining killer features based on hunches that are not based on behavioral evidence. Worse, they are hard to test without users actually adopting them. This is where a Diary Study might help to intercept hidden after-effects of use.