In design, human–computer interaction, and software development, interaction design, is “about shaping digital things for people’s use”.
Like many other design fields, interaction design also has an interest in form, but its main focus is on behavior.
Interaction design is heavily focused on satisfying the needs and desires of the majority of people who will use the product.
Interaction design begins with sketches…
…and later is implemented with professional tools (wireframe, mockup):
Similar wireframe, mockup tools are used like for information architecture, but with other goals than structuring the content, as for anticipating the user’s behaviour.
More about IxD here:
- IxD beginner’s Guide
- IxD Basics
- Interaction Design Association
- IxD at Wikipedia