They're great for linking to eco-conscious stories and spotlighting environmental issues.
One list recently provided by the OCA that I've found useful featured a rundown of "organic" health and beauty products that aren't actually as green as they appear. Check out a list here.
Sucks to find brands I've bought like Jason, Avalon Organics and Kiss My Face on the bad list. But good to know Dr. Bronner's (a backpacker's best friend) is still rockin' it pure.