interaction design - What affords scrolling?

Besides the obvious:

• Scrollbar


• Touch interfaces (especially mobile ones)


• A sign saying "You can scroll here you know!"

This for a desktop application.

Answer

Besides the obvious...

An indication that what is on screen is not the complete content. For example:

• 
  

  Text stops mid sentence

  
  


• 
  

  A border box shows no bottom but has the left and right edges stopping at the bottom. Even more emphasized if they have drop shadows.

  
  



• 
  

  Text or lists that cut off the bottom half of a line.

  
  


• 
  

  Pictures cut in half

  
  


• 
  

  Long text which has a contents list at the top but only a subset of which is visible - and no other way of 'paging'. Faqs are an example of this.

  
  

Basic mobile phones use a section indicator which is not interactive but just shows that for this page you are on section 1 of 4 for example.

Familiarity and similarity to other pages where the user has become accustomed to a page having certain content - in particular 'end markers'. An example of this might be looking for a submit button at the bottom of a form, or the comment field at the bottom of a blog entry. The textual footer links on many sites are also common expected end markers.