UK web development team Clearleft has released its web site usability testing application, Silverback.

In short, Silverback turns a Mac into a portable usability testing laboratory. What used to require a complicated and cumbersome set up involving several computers, a video camera, and lots of time, can now be done much faster and with less hassle. You only need a Mac with a built-in or attached camera, and a copy of Silverback.

The application records video footage of the user, and combines it with recorded footage of their activity on screen. Clicks, inputs, pointer movements and the user's speech and facial expressions are all combined into a single video file that can be quickly exported. One nice touch allows the test facilitator to add "bookmarks" during a session by clicking a button on the Mac's Apple Remote. Nothing distracting will show up in front of the user, but the bookmark is still recorded invisibly in the background.

The only thing that doesn't appear to be included - at least in this initial release - is the ability to edit the output video file before exporting. Even so, it looks like it could be an invaluable tool for anyone who makes software or web sites for a living. If you want to find out more, watch the five-minute demo video, which is a useful summary of aims and features.

Silverback is Tiger and Leopard compatible, sells for $49.95 and can be used as a fully functional demo for 30 days. As an added bonus, 10% of all profits generated will be donated to the Dian Fossey Gorilla Fund.