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

2009
Bright Green Retail
Alex Steffen explores some of the main components of a better and emerging model of shopping, wherein innovative companies are changing not only their stores, but how the whole experience of shopping works and what it means...

2008
Do Gas Taxes Cover the Costs of Roads?
Clark Williams-Derry is surprised to see that the Texas highway department says no, and suggests that there are lessons in this admission for road construction projects across North America...

2005
Elephant Pump
Jamais Cascio reports on the Elephant Pump, an improved version of the rope pump, designed by a group called Pump Aid...

Other recent "look backs":
July 20
July 21
July 22