I spotted an interesting little Twitter conversation between the Guardian’s editor Alan Rusbridger and Salon writer Glenn Greenwald last night. It started when Greenwald (@ggreenwald) said:

The Guardian slams WikiLeaks for endangering reformists in Zimbabwe, then sheepishly admits that *they* – not WL – did it http://is.gd/kAdiM

The link goes to a piece authored by James Richardson, a US-based ‘political and communications consultant’. The article argues that “WikiLeaks risks ‘collateral murder’ in the name of transparency,” with the release of US cables about Zimbabwe and prime minister Morgan Tsvangirai. Underneath the Guardian has made an overt correction that: “this article was amended on 11 January 2011 to clarify the fact that the 2009 cable referred to in this article was placed in the public domain by the Guardian, and not as originally implied by WikiLeaks”.

It would be surprising if Richard’s argument was the Guardian’s own view: it is not written by one of the paper’s staff journalists and it’s not an anonymous Editorial piece – it appeared in the Comment is Free section. But Greenwald saw differently, as the screen shot below shows. So, when does a newspaper’s comment become its opinion? And how should a newspaper make the distinction for its readers?