Offering consulting services in most aspects of interaction design. Located in California, USA.

Information architecture, interaction design, technical writing, user centered design, and usability evaluation. Located in Pennsylvania, USA.

Interface design and usability consulting firm which applies user centered design strategies to help businesses improve the user experience of their Web sites and consumer products. Located in California, USA.

Consulting services include business analysis, information architecture, user interface design, and usability evaluations. Located in British Columbia, Canada.

Consulting firm with focus on simplicity and usability. Located in Canada.

Tests and makes recommendations on how to improve commercial websites. Located in Tucson, Arizona, USA.

Offers web design services and features usability testing facilities. Located in Austria.

Offers Web design and usability testing services.

Sim D'Hertefelt offers services for designing usable interactive systems, includes articles. Located in Belgium.

Specializes in goal-based user interface design and field studies to find out the users' goals. Provides usability assessment, e.g. expert reviews and usability testing. Located in Finland.