Should Stack Exchange have a spam filter? (Does it already and I’m not aware?)

Question

Of course spam posts should be flagged, and if they come up in review, rejected.

Over on Mi Yodeya during the past 24 hours I’ve helped delete and reject four spam posts through the review queue, and I can only imagine that others were posted over the course of the night. To clarify, I’m referring to edits and answers that were about 99.274% words that I don’t think any decent person would use in everyday discussions, even if someone got them really angry.

Thing is, if the only thing we can do as a community is delete his posts/reject his edits, and as moderators to ban his account, can’t he just create a new account? Further, some of these posts . Maybe the mods can ban his IP address? I’m not one, so I have no idea what kind of power they wield in that respect. But he can always just get a new computer.

I don’t have the numbers to see what this is like on other sites, but I know this doesn’t happen often on Mi Yodeya. I wonder, then, whether this is the optimal solution, or whether an automatic spam filter be put into place - say, a new review queue that automatically deletes posts or rejects edits that can then be voted on whether to be reposted if it’s a false alarm. Perhaps it can be automatically triggered by certain keywords (like ****, %$#^, or @$+^).

Now, all of these posts that I voted to delete/reject came up in Suggested Edits and First Posts. Maybe such edits would show up in Low Quality in general, and that just wasn’t the case here because of precedence rules. I don’t know. But perhaps the above would be a better solution, if this is even as big of a problem as I’m making it out to be.

Answer 1

It should, and it does. The system is named SpamRam, and there are a handful of existing meta posts about it.

It gets trained by people like you flagging various badness. It works on first-class posts (i.e. questions and answers); not sure about comments or suggested edits. It's not account-based, but spammer accounts are typically deleted quickly through other means.

There's also SmokeDetector, a community project that tries (very effectively) to catch spam missed by other means.

Automatic word filters have been discussed and rejected to avoid "clbuttic" type problems.

Answer 2

In addition to SpamRam, used for posts, there is also a content filter used for suggested edits from anonymous (logged-out) users. From my experience with it, the filter covers a very wide scope and is frequently subject to false positives. When someone trips, their edit submission silently fails, and if they try to submit another edit, they'll see a notice that they've been banned from suggested edits.

Also, to reduce the incentive for spammers to spam via suggested edits, links to edits rejected as spam show as false 404 errors, so spammers can't show whoever's paying them a page with spam.