Great rules on best practises for corporate blogging by Nicolas Carr..
You (corporation) are getting into corporate blogging because you want to –
-Put human face to your corporate messaging
-Virally promote your side of the story
-Gain trust and credibility with the end user
-Be prepared for both positive and negative stuff – but are willing to do what is good for the customer
I certainly like his idea of having buddy and having a policy (lawyer stuff). Certainly the humans you put might err and say something stupid and it is possible that he/she might loose audience. But it is OK as long as corporation keeps away from the content he/she is putting out all they are doing is removing barrier to express opinions. And of course gain from the new insights about themselves they might get.