I respect his opinion and I’m not going to try and convince him to do otherwise. But I think it’s worth describing why I want comments on my blog and feel that they are worth having for many (possibly most) other blogs.
Types of Blog
The first thing to consider is the type of post on the blog. Some blogs are not well suited to comments. I have considered turning off comments on my documents blog  because it gets a small number of readers and is designed as reference material rather than something you might add to a public Planet feed or read every week as it has a small number of posts that are updated. So conversations in the blog comments are unlikely to happen. One thing that has made me keep comments open on my documents blog is the fact that I am using blog posts as the main reference pages for some of my projects and some people are using the comments facility for bug reports. I may make this the main bug reporting facility – I will delete the comments when I release a version of the software with the bugs fixed.
One particular corner case is a blog which has comments as a large part of it’s purpose. Some blogs have a regular “open thread” where anyone can comment about any topic, blogs which do such things have the owners act more like editors than writers. One example of this is the Making Light blog by Teresa and Patrick Nielsen Hayden  – who are both professional editors.
The next issue is the content of the post. If I was to create a separate blog for authoritative posts about SE Linux then there wouldn’t be much point in allowing comments, there are very few people who could correct me when I make a mistake and they would probably be just as happy to use email. When I write about issues where there is no provably correct answer (such as in this post) the input of random people on the net is more useful.
Another content issue is that of posts of a personal nature. Some people allow comments on most blog posts apart from when they announce some personal matter. I question the wisdom of blogging about any topic for which you would find comments intolerable, but if you are going to do so then turning off comments makes sense.
Finally there is the scale of the blog. If you don’t get enough readers to have a discussion in the comments then there is less benefit in having the facility turned on – the ratio of effort required to deal with spam to the benefit in comments isn’t good enough. In his FAQ about commenting  Russ claims that controlling spam “can take a tremendous amount of time or involve weird hoop-jumping required for commenters“. I have found the Block Spam by Math  WordPress plugin to be very effective in dealing with the spam, so for this blog it’s a clear benefit to allow comments. Since using that plugin my spam problem has decreased enough that I now allow comments on posts which are less than 1 year old – previously comments were closed after 90 days. The plugin is a little annoying but I changed the code to give an error message that describes the situation and prevents a comment from being lost so the readers don’t seem too unhappy.
The Purpose of Comments
Russ considers the purpose of comments to be “meaningfully addressed to the original post author or show intent to participate in a discussion“. That’s a reasonable opinion, but I believe that in most cases it’s best if comments are not addressed to the author of the post and are instead directed towards the general readers. I believe that participating in a discussion and helping random people who arrive as the result of a Google search are the main reasons for commenting. For my blog an average post will get viewed about 500 times a year and the popular posts get viewed more than 200 times per month, so when over the course of a year more than 1000 people read the comments on a post (which is probably common for one of my posts) then 99.9% of readers are not me and commentators might want to direct their comments accordingly. Of course a comment can be addressed at the blog author so the unknown audience can enjoy watching the discussion.
For some of my technical posts I don’t have time to respond to all comments. If I have developed a solution to a technical problem that is good enough I may not feel inclined to invest some extra work in developing an ideal solution. So when a reader suggests a better option I sometimes don’t test that out and therefore can’t respond to the comment. But the comment is still valuable to the 1000+ other people who read the comment section. So a commentator should not assume that I will always entirely read a comment on a technical matter.
Comment threads can end up being a little like mailing lists. I don’t think that general discussions really work well in comment threads and don’t aim for such things. But if a conversation starts then I think you might as well continue as long as it’s generally interesting.
Generally for most blogs I think that providing background information, supporting evidence, and occasionally evidence of errors is a major part of the purpose of blog comments. But entertainment is always welcome. I would be happy to see some poems in the comments section of technical posts, sometimes a Limerick or haiku could really help make a technical point.
Political blog posts can be a difficult area. Generally the people who feel inclined to write political blog posts or comment on them are not going to be convinced to entirely change course, but as there are many people who can’t seem to understand this fact a significant portion of the comments on political blog posts consist of different ways of saying “you’re wrong“. The solution to this is to moderate the comments aggressively, too many political blogs have comments sections that are all heat and no light. I’m happy for people to go off on tangents when commenting on my political posts or to suggest a compromise between my position and their preferred option. But my tolerance of comments that simply disagree is quite small. Generally I think that blogs which directly advocate a certain political position should have the comments moderated accordingly, people will read a site in the expectation of certain content and I believe that the comments should also meet that expectation to some degree. Comments on political posts can provide insights into different points of view and help discover compromise positions if moderated well.
How to provide Feedback
Russ advocates commenting to the blog author via email – it is now the only option he accepts. My observation is that the number of people who are prepared to comment via email (which generally involves giving away their identity) is vastly smaller than those who use Blog comment facilities. This means that you will miss some good comments. One of the most valuable commentators on my blog uses the name “Anonymous” and has not felt inclined to ever identify themself to me, I wouldn’t want to miss the input of that person and some of the other people who have useful things to say but who don’t want to identify themself. I have previously written about how not all opinions are equal and anonymous comments are given a lower weight . That post inspired at least one blogger to configure their blog to refuse anonymous comments, it was not my intent to inspire such reactions (although they are logical actions based on a different opinion of the facts I presented). I believe that someone who is anonymous can gain authority by repeatedly producing quality work.
Another option is for people to write their own blog posts referencing the post in question. I don’t believe that my core reader base desires short posts so I won’t write a blog post unless I have something significant to say. I expect that many other people believe that the majority of their blog comments would not meet the level of quality that their readers expect from their posts (posts are expected to be more detailed and better researched than comments). As an aside forcing people to comment via blog posts will tend to increase your Technorati rating. :-#
A final option is for people to use services such as Twitter to provide short comments on posts. While Twitter is well designed for publishing short notes the problem with this is that it’s a different medium. There are many people who like reading and discussing blog posts but who don’t like Twitter and thus using a different service excludes them from the conversation.
For my blog I prefer comments for short responses and blog posts for the longer ones. If you write a blog post that references one of my posts then please enter a comment to inform me and the readers of my blog. Email is not preferred but anyone who wants to send me some is welcome to do so.
If this post inspires you to change your blog comment policy then please let me know. I would like to know whether I inspire people to allow or deny blog comments.
-  http://www.eyrie.org/~eagle/journal/2010-03/008.html
-  http://doc.coker.com.au/
-  http://nielsenhayden.com/makinglight/
-  http://www.eyrie.org/~eagle/faqs/comments.html
-  http://wordpress.org/extend/plugins/block-spam-by-math/
-  http://etbe.coker.com.au/2008/09/13/not-all-opinions-are-equal/