Don't Back Down

As you may or may not know, I developed a Movable Type plugin a while back called MT-Moderate, to help me with the growing tide of comment spam. The plugin is simple. It's only 3KB, and involves installing only a single file on your server. No special modules are needed, and it works immediately upon installation. MT-Blacklist is great and Jay did a simply amazing job, but let's face it - I don't want to spend the time installing it or maintaining it. Enter MT-Moderate.

The idea behind the plugin is remarkably simple: Older entries typically have higher placement in search engines, a feature desired by spammers, so don't allow new comments without checking them first. If, by some chance, a valid comment was left recently on an older entry, and it has been approved, then allow more comments on that same entry, assuming the conversation has picked up again. Some people like to close comments on old entries, and that's not a bad idea, but it means that those occasional valid comments that do come in won't ever be left. I don't like that. Handling it this way actually addresses that.

You see, for the most part, older entries don't get (valid) comments. They get spam comments. As the entries move into your archives, people don't often find them when they are reading your blog. Out of sight, out of mind and all that. They might be found through a search, either on your blog, or through an external search engine such as Google, but I have found it very rare that people who find your blog through those methods will leave a comment.

Be realistic. It just doesn't happen that much. Most of us have a regular following that reads now and again, and occasionally comments on things. Those people will typically leave a comment within a few days at most. So by default, this plugin will moderate every comment that comes in that's more than a few days old. In the case of MT-Moderate, that default is 7 days. But other comments are still allowed - they just require moderation before they will show up on your blog. This prevents comment spam from showing up on your site, while continuing to allow valid comments to be left and approved as time allows, without having to close comments altogether.

If such a comment is left, and subsequently approved, then the clock resets slightly. Instead of the original seven days, it's reset to 1 day. This is because a new comment on an old entry is likely to start a new conversation very quickly or it won't happen at all. So if a new comment is left, and someone picks up on it, then subsequent comments will be automatically approved, so long as they happen within 1 day of the most recently approved comment (or are on a more recent entry). Out of hundreds of comment spam that I have received since creating MT-Moderate, only 3 have slipped through this test. Three! And one of those was before I shortened the "follow-up comment" period from 2 days to 1. I'd say that's a success by most any measure.