Google's Image Orientation Captcha

Google's new image orientation captcha is a good example of a productivity game. The core skill required is an ability to discern between an upright image and a not-upright, or incorrect, image.

Players use these core skills to work at re-orienting the images correctly.

The paper is here:
http://www.richgossweiler.com/projects/rotcaptcha/rotcaptcha.pdf

"Given a large repository of images, such as those from a web search result, we use a suite of automated orientation detectors to prune those images that can be automatically set upright easily. We then apply a social feedback mechanism to verify that the remaining images have a human-recognizable upright orientation."

CNET http://news.cnet.com/8301-17939_109-10222514-2.html?tag=newsEditorsPicksArea.0
PCWorld: http://www.pcworld.com/businesscenter/article/163334/google_offers_top_tip_to_help_beat_bots.html

Tech Blorge: http://tech.blorge.com/Structure:%20/2009/04/19/google-tries-out-picture-captchas/

View an archived version of the Productivity Games webinar

PDF of presentation with speaking notes
Also includes links to some of the research and sources that were discussed