The illusion of completeness is a usability issue, leading users to miss out on relevant content on a web page. This occurs when users do not realize that there is more content to be explored on a page because the design suggests that they reached the end of the page, and there is no need for more scrolling.
While this is a handy heuristic, only research done on actual users can validate your design.
How does it happen?
Large hero graphics/image take up all the space above the fold and there is no or only weak visual cue for the user to scroll
Large image above to fold, with a “LEARN MORE” call to action button
2. A clear horizontal line, or other segmenting element (such as expansive white spaces, advertisement, social sharing icons) lead the user to assume that they reached the end of the content offered on the page.
How to Avoid it?
The goal is to avoid sending the message that the reader has reached the end of the page.
You may want to choose a smaller sized hero image or carousel so that they do not take up the whole “above the fold” area.
Make sure that the white space between sections is not too wide
The horizontally neighboring segments should not all start and end at the same spot. Here is an example from the Startribune (retrieved on 1/4/2017) . The small news segments in Column A always end at a different point from where Column B’s segments start or end.
or so the thinking goes. But designing for mobile poses unique challenges
“Mobile users are different. They demand experiences that are more engaging than what you offer your desktop customers but are constrained by limited screen real estate, time, and capabilities”
(see this useful primer on mobile users). Sounds like a tall order? So what is a mobile designer to do? It all depends on the goal behind the mobile presence. Read on.
Responsive, Adaptive, or Stand-Alone Design?
The question you want to ask though is why users want to visit your website on a mobile gadget.
Does your website enable people to do something that users often do on the go, such as finding out the hours of a business, or buying tickets, or looking up and calling a phone number?
Or are the goals of your website better explored on a larger screen, and the mobile presence is required only as a starting point for further exploration later on. So maybe they want to save the URL of your website or save a longer article for later reading.
Your mobile design will depend on the tasks users can accomplish on your site. Does your site allow for exploration that may be better done on a larger screen? You may be better off using responsive or adaptive design, which allows the same content to flow onto different sized screens. Same content, same interactions, just parsed differently. The difference between the two designs (responsive and adaptive) has to do with the how the content changes in response to screen width. Responsive designs respond fluidly and continuously as you resize the screen, whereas adaptive designs change in “snaps”, or jumps, when another set of specification makes more sense. Say when changing from a cell phone to a tablet.
But if you have mobile -specific tasks to accomplish, then you may opt to develop a website which is independent of the full website, designed to focus on the most relevant goals mobile users have. For example, when designing a mobile site for a public library, you may only want to enable the users to
find out about locations and hours of brick-and-mortar libraries
check the patrons’ account, enabling the users to view what they have out, and what they need to return/renew
search for an item and then request it
This scenario calls for a standalone design, with the mobile application focusing on the high-frequency on-the-go functions, and the full website going beyond that and including more.