Building community – or not...

The comment field makes a blog a two-way conversation, turning it from a collection of pages into a community. You present your point of view, and people comment on it. Often this garners feedback, new ideas and constructive criticism. Other times it turns into a spigot for spam. If your blog is private or not that popular, you can probably get away without restrictions on comments. But the evil spam robots will eventually find you (often before your real audience does) and start posting comments like "Great post! Love your blog! Buy Viagra here!"

Actually, you'll be lucky if the spelling and grammar are that good...

A few options exist:

1. Turn off comments. That may be a bit extreme, but if you don't have the time to react to comments on your blog, it won't be much of a two-way conversation anyhow.
2. Limit comments to registered users. This doesn't really stop the spammers as they have accounts on all the major blogging engines. As fast as those accounts get deleted, they make a new ones. Not recommended without one of the following options.
3. Require a CAPTCHA, a Completely Automated Public Test to tell Computers and Humans Apart. This is the least intrusive, most spam-deterring method available and I highly recommend it for any public blog. A CAPTCHA presents a distorted picture of several letters to the user and requires them to be identified before the comment is accepted. More complicated versions, such as reCAPTCHA, use the human interaction to do cool things like converting ancient New York Times print articles into digital format.
4. Require comment moderation. This is the best option for very popular public blogs. While the Viagra spam-bots will be deterred by a CAPTCHA, some humans are nearly as hideous. These "trolls" live to stir the pot with inflammatory or derogatory comments. Perhaps that's the kind of conversation your blog was meant to have. If not, one or more administrators will be required to approve comments before they appear on the site.

All of these options can be set by following the "Dashboard" link, followed by "Settings," then "Comments". The CAPTCHA settings is called "Show word verification for comments" on that screen. Until your blog gets so popular that your Inbox is flooded every morning, it's a good idea to add your email address to the "Comment Notification Email" box so you know when the world talks to you.