The act of reviewing third party comments or content to ensure compliance with terms of service or community guidelines. Content can be pre moderated, meaning it is reviewed before being published (e.g. a word filter will pre-screen comments and block profanity before being posted on the site), or post moderated, meaning the content goes live immediately but a moderator may take the content down at a later point in time if they find it violates their rules. Moderation is usually carried out by a combination of people and technology tools.