Technology Weblogging

Comment spam prevention in Wordform

I believe that, eventually, most comment spam strategies will have to have a system-wide component in place to truly combat this problem — something to watch for comment spam patterns happening on a server, and throttle accordingly. However, that’s something that can’t really be handled with the application. So, I’ll focus on what I can do in Wordform.

My comment spam protections are not going to include a blacklist, in any shape or form. These require too much processing, and are too vulnerable to corruption. Instead, I’ll use a variety of techniques that combined should protect a site — even a heavily hit site.

First, I’ve added individual comment moderation so that you can turn moderation on for a specific post, or a group of posts. When this is turned on, a message will show near the comment form stating that the comment is currently moderated.

Next, I’m adding new capability to search in comments for those that fall into a range of dates, and then be able to delete all comments that match a search criteria. With this, if you do get hit, it should be easier to delete the spam.

(I’m also adding a one-touch button to globally approve, or delete, all moderated comments.)

The comment posting page will have a throttle that can be configured in options. This throttle will check the number of comments received within a certain period of time, and if the count exceeds a value that the user can specificy, will either moderate the comment, or deny it (again, something that can be configured). At Burningbird, the throttles are no more than ten comments in a minute (a WordPress option); and no more than 50 comments in a day (my option). These two values can be changed, and I’m also adding a maximum count for number of comments allowed in an hour. All of this will prevent ‘crapfloods’, which can overwhelm a site, and even a server.

Currently I’m using database queries for the comment throttle I have at Burningbird, but for Wordform, I’ll be using other caching methods to hold timestamps and comment counts. This should make the throttle lightweight and robust.

I’m also adding a configurable option to either close or moderate all comments over a certain number of days old. I use this with Burningbird, whereby the first comment to a post over so many days old gets moderated, and then the post gets closed. This has eliminated probably about 98% of my comment spams, while still giving me the option of determining (from this last comment), whether I want to keep the post open, but moderated.

A new functionality for Wordform not currently implemented at Burningbird is the ability to close a discussion. By closing a discussion, the post (or the web site) is temporarily put into a lock-down form, where only those people who have previously written published comments can add new comments. When they do, the comment is posted immediately. If a person hasn’t added a comment previously (based on the person’s email, which is a requirement for lock-down, though it’s not printed), their comment will be put into moderation.

Finally, I’m experimenting around with a new comment spam prevention method that I’m calling “Stealth Mode”. However, this is one item I am leaving for a “Ta Da!” moment when I release Wordform’s first alpha release.

(Most of these comment spam moderation techniques will also apply to trackbacks. I’m currently wavering on my support of pingback, which is really nothing more than recording a link, and this is accessible via the vanity sites.)

Between all of these–Throttle, Lock-down, individual and weblog moderation, better comment management, closing older posts, and Stealth Mode–the comment spam problem should end up being no more than a minor irritation in Wordform. Then if I can just get people to accept that comment spam is not an invasion of a person’s personal space, and that it’s a way of life and to not spend so much time fretting about it, we’ll have the comment spam problem managed.

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