SEOmoz is pretty lucky when it comes to blog comments in that we receive a lot of them. By most blog's standards, our regular count of between twenty and sixty comments is quite enviable, trounced by the likes of Techcrunch but highly competitive in this industry. We also keep a relatively good record of the comments our members make and how well received those comments are via Mozpoints and the record of recent comments we keep on everyone's profile.

Two things we often fail to address is what our - or any website's - comments say about the state of our community and what the best comment protocol is for encouraging a productive commenting environment.

Whether they mean to or not, bloggers often write to the people they believe are reading their work. We know that we have "lurkers", as much as I dislike that term, who read blog posts but never comment, but since we know the names, faces, styles and opinions of those from whom we receive feedback, we sometimes focus on them. Thus, the makeup of a blog's commenters makes at least a small difference to its content.

Many websites can make guesses at how their community has changed, but here, we can record it with precise scientific accuracy. Or through a made-up system of points that appeals to geeks. When SEOmoz first calculated Mozpoints in February 2007, the scores were arrived at through participation alone: obviously, no one had ever voted on anyone else's contributions at that stage. This is what our contribution hierarchy looked like on February 10, 2007.

In contrast, here is our ranked users page now. It looks a little bit different. How, as a blogger, should you analyse these changes? Why did users such as simmal_tree (whose user name is now kulpreet_singh) taper off their commenting? Did he - and other previously active users, of which there are many - lose interest in our site? Did they become too busy to participate in online communities? Did they move away from the search industry?

Our community hasn't changed drastically enough for us to really need to take a look at who we've lost or who is less active, but I believe that a system like ours is worthwhile for sites that maintain a large readership. Measuring both contribution and recognition (through votes) allows a website's owners to monitor both changes in a site's demographic, but in contributors' values.

I ask you this: if you've been reading and participating in SEOmoz discussions since, say, early 2007 or before, what do you think has changed here? Do you remember V2 with its brown and orange tones? Do you remember a time before floating comment boxes and user generated content? How is your interaction with SEOmoz different now than it was then?

A secondary concern I have with comments is how best to implement a commenting system. This seems to be less important in the quest to keep readers, but significant nonetheless. I think ours is very good, only we do hear the occasional complaint about our login requirement.

I like a system which has users log in and maintain a profile for the following reasons:

1. It promotes slightly more responsibility. A person's comments are archived more accurately and a profile acts as a small portfolio. Users' profiles often rank well in search engines and should give people more reason to be considerate about what they write than if all they're required to do is leave a name and email address. Of course, this often doesn't stop people from making ridiculous comments, but it helps filter out trolls who can't be bothered creating accounts in order to be negative. Sadly, it keeps out positive commenters too.
   
2. It slows down spam. Whilst hardly stopping it, login requirements add one more obstacle for the Furberry and Fauxlex merchants.
3.  It creates a sense of belonging that makes people return at a higher rate.

I also recognise that it has its flaws: Non-members are less likely to comment, even if they have something valuable to say, because our attention spans online are short and the couple of minutes it takes to create most accounts is too long. Darren Rowse at Problogger presents the view of someone who does not like logging in:

There is one situation where I rarely leave a comment - even if the post deserves it - blogs that require me to login before making a comment. Maybe I’m lazy (actually there’s no maybe about it) or maybe there’s something inside me that worries about giving out my personal details - but when I see a comments section that requires registration I almost always (95% or more of the time) leave the blog without leaving the comment that I want to make.

The three types of comment systems I see most regularly are those which make someone enter their information every time, those that remember returning visitors, and those which maintain accounts: