The European Perspective
Skating on natural ice is much more organized in Europe than in North America. There is a long tradition of large scale public skating events and many skating clubs. Sweden and Holland in particular have a combination of lots of frozen lakes and ocean areas and a large, outdoor oriented, population. This has generated the critical mass needed to develop a good scientific understanding of risks and practices that are effective for reducing these risks.
There has been quite a bit written on ice assessment, behavior and science. Most of this is in Swedish or Dutch with only a little in English. We have much to learn from the broader European experience.
Links: The following are links courtesy of Dave Dermott and Sven Andersson.
Dave has compiled a large set of articles and links on ice skating and kick sledding.
The Ice Handbook for Engineers: A good and practical overview of ice science written by Lennart Fransson. It covers sea ice as well as lake ice.
Sven Andersson's blog has a nice overview with lots of links.
The Think Ice website has several excellent articles on ice behavior. http://www.thinkice.com/
In particular, Johan Porsby's comprehensive page Situationsanpassad isvbedoming ('situational ice judgment') covers all reasonable forms of skateable ice (and a few that are not so reasonable). http://www.thinkice.com/glaciology/sv/situationis/situationis.htm
A couple other Swedish ice safety links:
From Johan Porsby December 12th, 2011: a two minute, skate level, video of a tour, just a subway ride from Stockholm on great ice and a blue bird day.