1. A computer-implemented method, using a processor, for generating an opinion summary from a document, said method comprising: using at least one of syntactic analysis, semantic analysis and discourse analysis to assist in automatically extracting a plurality of opinion expressions from the document using the processor, each opinion expression identified by a grammatical element and associated with an opinion source, opinion topic, opinion polarity and opinion strength, wherein for each opinion expression the opinion source is at least one person or entity to which such opinion expression is to be attributed and wherein the document includes opinion expressions from a plurality of opinion sources; identifying those opinion expressions that share a common opinion source and a common opinion topic using the processor; and combining the opinion polarities and opinion strengths of those opinion expressions that share a common opinion source to form an overall opinion summary with one aggregate opinion frame for each common opinion source-topic pairing.