Invloed van blogosfeer overdreven?

Companies absolutely need to keep track of the blogosphere. I agree with that. However, I think it is only a segment of what companies should look at for their marketing and publicity plans. There are millions of blogs, but what are the audiences of these blogs? We know that lots of teens and college students have blogs and, mainly use them to communicate with friends and family. These are our customers, but are they going to corporate blogs? Not so sure about that.