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

2009
Lewis Hyde and The Enclosure of Silence
Ethan Zuckerman explores the history of "the commons" and the growth of the enclosure of intellectual property, even silence, or unknown possibility, which we do at our own risk...

2008
Chinook Salmon Invade South America
Sarah Kuck reports on the unexpected growth of Chinook Salmon habitat in South America and how the study of this phenomenon can help researchers better understand how to manage North American fish more wisely and institute appropriate recovery plans...

2005
Invention Resource Database
James Cascio says "This is what the future could look like." The Invention Resource Database (or InventionDB) is a database of open-source hardware projects, designs and information...

Other recent "look backs":
June 14
June 15
June 16