There are several types of spam to deal with regarding blogging: comments, backtracks, and email harvest.
Comment spamming occurs when a comment is left in response to an article with a link to a spam site.
Backtrack spam occurs when spam links are left as backtracks.
Email harvest occurs when an embedded email is taken off the blog’s page and used for spamming.
How do we prevent this?
CAPTCHA (Completely Automated Public Test to tell Computers and Humans Apart) shows convoluted alphanumeric characters and has the user type them in. This method has become very popular recently in order to stop automated programs from creating accounts though some people will not deal with sites that use CAPTCHA.
Several suggestions are available for comment spam.
- Moderate comments. This is very effective.
- Visit left behind links in comments to make sure they point to good sites.
- Have the user register in order to post a comment.
- Use CAPTCHAs during the registration process so it cannot be automated.
- Limit the number of links per comment (check admin screen)
Some blogs have black word lists that you can add your own words so if they appear in a comment the comment is rejected.
Authors can be preapproved so their comments do not have to be moderated.
Backtrack ideas:
- Turn off backtracking. Drastic but effective.
An email address can be embedded using JavaScript to hide the fact that it is an email address.URL blacklists, where any URL left in a comment is checked against a blacklist, is effective but difficult to maintain. There are several public ones available. For example, Wordpress has the akismet plugin which checks the spamminess of a comment anonymously.
A proposal to reduce spam, backed by Google, Yahoo, and Microsoft, is add an attribute “rel=nofollow” to any embedded links in a comment or trackback. The search engines, upon encountering this, will not use the link in calculating ranking. Some blogs automatically default to adding the nofollow attribute to links.
Doug
