Im preparing to push my site live and I wanted to hear the opinion of others about the commenting system, in regards to anonymous users.
One of our goals is to continually build our member base. By forcing users to register before they can leave comments, we are ensured that active participants within our site are registered, and I would assume this cuts back on comment spamming as well as the random "This site sucks" type of comments. If a user genuinely wants to post a comment, then the procedure for registering, checking email, and validating that member shouldnt be an issue.
That being said, I do realize that there are certain benefits of allowing Anonymous users to post comments. The first being quantity of content. I would assume (and correct me if Im wrong) that by allowing Anonymous Users to post comments, your stories/blogs/pages will receive more comments, which make the overall site community-feel look more active, and established.
From a users perspective, if most of the submitted content has 10+ comments each, as opposed to 0, 1, 2, or 3 comments each I would be more inclined to join that community as I would feel that it has already been established, somewhat.
Again, this is applying to a new site that has not launched yet; not a site with thousands of members.
I also realize that a bulk of our traffic (Im hoping) will be coming from the search engines directly to a specific page on our site. The attention span of a typical user coming directly from a search engine without any prior knowledge of our site is minimal. If they are interested in posting a quality comment, I would want that procedure to be as easy as possible for them. I wouldnt want to force a user to take 3 steps, validate an email, then go back to the site. I have a feeling that the drop-off rate of users wishing to comment and the necessary steps needed to take in order to comment are directly related.