Conceptboard
Browser-based visual collaboration.
Process On
Web-based diagram tool.
Notism
Design collaboration tool with Basecamp integration.
Spacedeck
Visual collaboration for teams.
Google Sketchup
Simple 3D modelling software.
Amazon Storyteller
http://studios.amazon.com/storyteller
Web-based storyboarding platform.
Greenhouse
http://www.oblong.com/greenhouse
Prototyping tool for spatial interfaces.
Touchpoint Dashboard
http://www.touchpointdashboard.com
Web-based journey mapping tool.
LiveSurface
http://www.livesurface.com/context.php
Context prototyping app for real world visualisations.
color.hailpixel
Simple, browser-based colour palette tool.