PepsiCo continues to bring its do-gooder message to its vast social media following, this time partnering with Waste Management and Keep America Beautiful on a major green effort to help, well, keep America beautiful. Weapon of choice: the “Dream Machine”. Delivery method: blogs, Facebook, and Twitter.

You can read about the details here, but the concept is pretty simple. Pepsi will place specially designed recycling bins in key places like gas stations. The location is chosen by you. And, when you recycle a bottle you will receive points that you can redeem for prizes.

Greenopolis.com is the movement’s primary internet hub. Here you can brows events, check out one of their many YouTube videos, and, most importantly, claim your prizes. Facebook is an important factor, too. You can keep up on the news and share your save-the-planet activity with your friends. In all, they already have over 27,000 Likes between two pages. Here’s just one of their flashy Facebook recruiting messages:

They are taking Twitter seriously, too. They already have over 12,000 Greenopolis followers there, and they are tweeting several eco tweets an hour. Here’s just one of the very many tweets:

All this social media activity doesn’t take us by surprise. Earlier this year the company initiated a major online campaign called the Refresh Project, which was also a civic-minded publicity project. It’s still going strong with over 680,000 “Likes” on their Facebook page, quickly cementing the company’s do-gooder and green reputation with the Facebook generation.

What about Coca-Cola? They are fighting back with their ongoing “Happiness Machine” stunt where Coke vending machines reveal bigger prizes for unsuspecting college kids. Okay, it may be much less virtuous, but just as vital. In just one Youtube video they gathered over 2 million views in a few months.

Nevertheless, Cocal-Coal appears to be losing in the head-to-head social media taste test. The Greenopolis push is Pepsi’s second major advertising campaign that makes full use of social media to spread a worthy message: give your customers (young adults) the chance to save the world, and deliver it to them in the place they hang out most.

Editor’s Note: PepsiCo’s B. Bonin Bough, global director of digital and social media, will be detailing at the Social Media Influence conference on June 22 how PepsiCo is using social media to create a more meaningful dialogue with the public. Register before May 1 and you can qualify for the early bird rate.