Each of us knows you need to listen to the users' feedback in order to succeed. We can never predict the future. The wisest thing we can do is to try to create a good thing, and then monitor the reaction of people and change the product in the appropriate direction. Good clothing manufacturers, such as Zara, do so. Good authors, such as Paul Graham, value the opinion of their readers most of all. One of the main advantages of Web applications compared to the desktop is that developers can constantly improve them, basing on users' feedback, and users see the changes instantly.
Commenting is the most common way of getting feedback on the web. All blog engines have implemented this feature. People comment on the video on YouTube and photos on Flickr, as well as news on Reddit and Digg. But is this the easiest way for users? I think no. Imagine a situation that one of your readers is very busy and has been able to devote only a few minutes to read the post in your blog. Will he leave a comment? Most likely, no.
Consider another situation: you didn't want to write, but you have forced yourself to do so for any reason. The result was the post that was less quality than usually. You have published it, and forgot about it. Will your readers tell about this in the comments? I think not. I do not take trolls into account - they will be happy to express their "opinion". With regard to good readers, they are likely to prefer "not to notice" your mistake. Perhaps some of them simply stop visiting your site. The most loyal readers will remain. But the worst is that this post will make a bad impression about your site for visitors coming for the first time. And all this because of the fact that you didn't get a signal at the right time.
You will not probably deny that the part of the visitors of your site are introverts. They also have their own opinion, but it is difficult for them to express it, so they rarely leave comments. And if this is the only way of feedback on your site, you are missing a part of your audience.
Another situation. You have written documentation for a program that you've created. The only thing you want to know is whether the information is useful and clearly presented. Is the comment the appropriate way of feedback in this case? Probably not.
In general, commenting is not a tool of evaluating the quality of the post. "Great article" and "You suck" are similarly bad. Commenting, in my opinion, is a tool of expression of users' opinion on the topic. At least, good comments.
Understand me correctly - I am not an enemy of commenting. All posts in my blog are opened for commenting, and I delete only trolls' comments and spam. If the reader expresses his opinion (no matter in my favor or not), the comment is always published. I just want to say that commenting is not the only and enough way of getting feedback, it is not suitable for all cases and is not an objective tool for evaluating the quality of the post.
What do I propose? In my opinion, in many cases it would be wise to use a system of voting along with commenting. You want to know whether your readers liked the article? Just ask them about it, and they will answer you. I propose the arrangement: if the user wants to express his opinion about quality of the article, he uses a system of voting. If he wants to express his opinion on the topic of the article, then let him leave a comment.
I didn't invent this. Reddit, Hacker's News and Digg successfully use this system. They combine the systems of voting and commenting, and use the number of votes as an assessment of the quality of the post. And this, in my opinion, is the best approach. Even the busiest reader will find time to vote - that would require less than a minute. If the article would be very bad, readers simply give the lowest rating. For introverts it will not be difficult to evaluate the article. As a result, you will have a more complete picture of what people think of your article and of its topic.
In my spare time, I wrote jQuery plugin called Sexy Vote, which is a widget for voting on the site. It is very simple to use, but offers several possibilities for the configuration, so you can easily customize it to fit your own needs. I will be very happy if it becomes useful for some developers.