And when the audience can't talk back? Well, that both takes us back to where we were and changes everything.

This is Andrew Bolt's blog we're talking about, an extraordinary forum, the self-proclaimed "most-read political blog in Australia".

Without doubt it is one of the most popular, robust, vigorous and influential spaces for discussion around politics and a certain emphatic line of conservative thought on the Australian web.

Bolt saw the possibilities early and has stuck to his guns, devoting extraordinary time and energy and providing that essence of successful blogging, dependability and persistence. As a result, he's built ... well, more than an audience, audience is very old school ... as a result, Bolt has built a community.

This is where a blog like Andrew Bolt's derives its authority and social power. One guy churning little bursts of angry opinion into the ether is one thing. Someone writing round the clock for the benefit of a constantly engaged audience capable of quick time response and discussion is quite another.

That person has access to the geometrically expandable power of community; quite a step up from mere audience.

And that, until this month, is where things stood. The Andrew Bolt blog was a well-read fixture for political enthusiasts, never mind their particular ideology. It routinely clocked in the vicinity of three million page impressions a month (an audience of similar size to The Drum).

It's hard to tell which components of the Bolt brand ... the columns, the blog or the TV show gives Bolt his authority and influence, but he enjoys both. He has the capacity to shift the flow of public thought on his pet topics. He campaigns. He's a voice.

So, if you published him, why would you want to unpick that?

Melbourne's Herald Sun is host to Bolt's blog; it's the biggest selling newspaper in the country, and the first of the local News Limited tabloid-based websites to deploy a paywall. This month the decision was taken to cut Bolt off at the knees: to slash his comment moderation. Bolt told his readers on July 2:

Apologies. Staff cuts mean fewer comments will be moderated (which is why some threads have none showing). There will be no moderating of comments submitted after 5pm. Some readers have asked why we don't just put up all comments, or allow a report-abuse system of control. Blame the restrictions on free speech in this country and the lawfare conducted against this blog. The legal risks are far too high. Result: less free speech for fear of being punished for "bad speech". Press Council take note.

Take a look at the Bolt blog now and you will see post after post with no comments, perhaps one open thread each day. What you see is Bolt paying the price for popularity and success.

The truth is that to run comments at high volume in the angrily contested space that is modern Australian politics requires diligent pre-post moderation. And that means staff. And that means money.

There's proof here that all the talk of faltering media business models cuts a little deeper than the routinely discussed disconnect between classified advertising and serious broadsheet journalism. Here we have the country's most successful political blog neutered thanks to the cost of moderation.

It's tough all round. Moderation is a constant drain on the resources of this site. At News Limited's The Punch, it's a burden shared by the staff of four. Individual bloggers at The Australian look after their own comments. Little wonder that Peter Brent, an early adopter in the Australian political blogging scene, tags his Mumblepolitics posts with the earnest plea:

Comments short and on-topic please.

The decision to reduce moderation, and therefore comments, on the Bolt blog is evidence that despite its bold strides into the online, the Herald Sun is selective in what reader communities it values.

Supercoach football is one thing; a sometimes obnoxious, somewhat loopy, but perpetually engaged political mob quite another. The key difference is presumably the capacity to monetise, as they say, that audience engagement.

There's a deeper discussion here on how the new imperatives of life online, the necessity for profit, will shape the sort of content that major publishers will choose to support. We may be watching the end of an experiment, confirmation that what worked in the quieter confines of the non-mainstream internet can be a problem for a conventional publisher.

And there's another turning point here, a critical moment for a very effective political voice.

Will Andrew Bolt still pack a punch without the constantly visible and engaged backing of his online audience? How much of a blog's appeal comes from its author-produced content, and how much from the community discussion that follows it?

Without this avenue for engagement, is a blog still a blog? And if not, what is it?

Jonathan Green is presenter of Sunday Extra on Radio National and is the former editor of The Drum. View his full profile here.