Looking back one, two and five years ago today on Worldchanging:

2009
Book Review - Experimental Geography: Radical Approaches to Landscape, Cartography, and Urbanism
Regine Debatty reviews this lavishly illustrated book that explores the distinctions between geographical study and artistic experience of the earth, as well as the juncture where the two realms collide (and possibly make a new field altogether)...

2008
Misunderstanding Cyberwar
Ethan Zuckerman examines the 'is it' or 'isn't it' cyberwar between Russia and Georgia...

2005
Re-Introducing the Wild
Jamais Cascio discusses Josh Donlan's paper "Re-wilding North America" which argues that a range of megafauna once found (in somewhat ancestral form) in North America should be gradually re-introduced the American mid-western plains.

Other recent "look backs":
August 13
August 16
August 17