A few years back, when I worked for a large global company, a major NGO launched a campaign against us. I found it fascinating how so many people felt it was a major campaign by that org (no, it wasn't). Actually, from their side, it was simple. One of their directors wrote an article for the Guardian, then their network of Blogs and MySpace accounts posted links to it with a "call to action" (call/fax/email "us"). This had a significant impact on us, and received a fair amount of media coverage.
This campaign utilized very few resources on the NGO's side. The largest effort was the writing of the article. Well, that's in regards to the campaign. The real work for this was years in the making. They built and maintained a large, global network of advocates. The NGO interacted regularly with them. Information was shared, input solicited, and the audience was listened to. Relationships created and maintained with two-way discussion. Then a blend of MySpace (it was a couple of years ago) accounts (pretty much every college branch had it's own page), email newsletters and alerts, and a trust relationship made executing this easy and fast.
This relationship was key. Social Media simply provided the tools for speed. Relationships are THE currency of NGOs and activists.
Businesses (well, any org) can't wait until the crisis to engage and expect to be accepted as anything other than defensive. Business' long history of spin and abuse produced a legacy of distrust. Sure, this is generalized out, perhaps unfairly. It can be whined about, or embraced and dealt with.