Going Green - Real or a Fad?

When Walmart goes green you have to question this whole "green" movement. Don't get me wrong, I think it is very important that we find ways as individual consumers as well as corporations to conserve the natural resources of our world. But I'm wondering if companies like Walmart are dedicated to this movement because this is a part of their social mission or is it because "green" is popular and they are using it as a ploy to gain more customers. What I mean is, is this "green" movement for real or just a fad? I sure hope it's real but I'm holding my breath, especially when Walmart the uber-exploitative company it is, decides to jump on the bandwagon.