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

2009
Nothing for today!

2008
One Approach To Sustainability: Work Less
John de Graaf argues that to create a sustainable society, we’ll need to work less to have more of what we truly need: time...

2005
Engineering with DNA
James Cascio reports on the recent research of nanoscientists and biochemical engineers that are starting to play with DNA not as replicating code, but as physical tools for nanoassembly...

Other recent "look backs":
June 16
June 17
June 18