Charcoal is a volunteer, user-run group that aims to detect spam on the Stack Exchange network and remove it as quickly as possible. We do this with the aid of some software that we’ve written, called SmokeDetector.
Even if you are unfamiliar with the Stack Exchange network, you may have heard of or even participated on its flagship site for programming questions, Stack Overflow. The rest of the network contains hundreds of similar sites about various topics, including law, photography, and cooking, among others.
The Stack Exchange network empowers and strongly encourages its users to participate in quality assurance and moderation of the content on its sites. We in the Charcoal team are, generally speaking, regular users who are doing what we can to make the best of this mandate, and help enforce the anti-spam and anti-abuse rules that the network community as a collective have established.
Stack Exchange also has a reputation system which gives users more control over moderation tools as they earn the trust of their peers. For example, an anonymous visitor or a new user can’t flag posts or participate in chat.
On a typical day, we process on the order of a hundred spam reports across the network. Identified spam is deleted when enough users click a button to flag it as spam; we expedite and to some extent automate this process to the point where spam is often deleted within seconds of being reported.
Reported posts (some of which will be identified as false positives, i.e. not spam) are archived in a back-end system called metasmoke where you can search for posts and see various metrics we collect.
If you are a registered user on the Stack Exchange network and have earned the privileges to participate in chat, please feel free to visit the Charcoal HQ chat room where most of our activity takes place.
There is more information about the technical implementation of our system and the processes we have developed around it available around our website.