350 parts per million is the level of CO2 many climate scientists agree is the safe upper limit of carbon in our air (we’re at about 390, by the way). But that’s not all 350ppm is. It’s also one of the strongest examples of social media optimization the world has ever seen.

To help promote its International Day of Climate Action (last Saturday, 10/24), 350.org simply asked supporters to use a special hashtag in related tweets: #350ppm. According to search.twitter.com, it was used 1,500 times over the weekend (10/23-10/26).

The Day of Climate Action was a rousing success. 181 countries participated (meaning fewer than 15 didn’t), and there were 5,245 events across the globe.

As for SMO success, 350.org now has over 10,000 Twitter followers. They’re ranked #43 in the “Everywhere” region (via Twitterholic). 350’s most recent Influence score from Twitalyzer is a “profound” 64 of 100, after a recent increase of 31,900%. Twitalyzer bases Influence on Reach (followers), Authority (getting retweeted), Generosity (RT’ing others), and Clout (getting mentioned). 350’s Clout score is 100 of 100, unchanged in the recent past.

On Sunday, 350’s Day of Climate Action was the most talked-about news story on the planet – tops on CNN, The New York Times, Le Monde, Google News, and more. The top Google headline was “Campaign Against Emissions Picks Number,” due in no small part to thousands of participants using “350.” For Sunday and Monday, the story of 350 got more impressions than any other in the world.

Bill McKibben, founder of 350.org, knows nothing would have been the same without today’s technology: “Some journalists have described the whole sprawling day as a ‘beta test for the wired world.” Read more of
Bill’s reflections on the day.

One '350 Action' photo includes three groups of activists along the Dead Sea (left to right): Israel, Palestine, and Jordan.

Though not intended for tracking purposes, a visual representation of “350” was requested in participants’ photo submissions. As it turned out, photos from Australia’s, China’s, and New Zealand’s Saturday events served to fire up supporters preparing for the Saturday rallies on the other side of the world. Organizers even displayed hundreds of freshly submitted photos on screens during an event in Times Square.

350’s slide shows keep growing and growing. The total has topped 19,000 photos, plus hours of video. Check out 350’s flickr stream.

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