Abstract: This invention provides a method and apparatus for identifying potential errors in a block of text using rules contributed by a plurality of users. Each rule consists of a pattern (which matches parts of a block of text) and a message (which provides helpful information). A group of rules is applied to a block of text to generate a report that binds messages with sites in the text where the corresponding rule patterns matched. Users can create, organise, edit, publish, rate, and combine rules and groups of rules. User ratings are used to generate better reports. The invention has many potential embodiments, with a web interface being an exemplary embodiment.