What is a good approach to an anti-spam algorithm for a website similar to reddit? Their anti-spam algorithm seems awfully broken (banning on words in the title and doing a horrible job for that matter). Considering a post spam because it has the word 'spam' in the title is really not a wise choice. Anyway, how can one approach such problem ? Are there any tools that help in such cases? Also, what are the /technical/ reasons behind reddit's choice not using reCAPTCHA on every post submission? It seems like a much better solution than what they have right now. Since reddit is basically a community-driven website why not give such power to the communities' trusted members?