Via LifeClever, news of a feature of the New York Times web site I didn't know about: Double-click on any word in a story to pop up a window of reference information about that word.
This is BrainLog, a blog by Dan Sanderson. Older entries, from October 1999 through September 2010, are preserved for posterity, but are no longer maintained. See the front page and newer entries.
May 3, 2007