1. A method for estimating a sentiment for an entity comprising: providing a sentiment dictionary having a plurality of sentiment terms, each sentiment term having assigned a sentiment value, at least one of said sentiment terms is associated to a group context; defining a context for estimating the sentiment of said entity as a query context; screening at least one text document for occurrences of sentiment terms being associated to a group context corresponding to the query context; and calculating a sentiment score value as a function of an occurrence of a sentiment term being associated to a group context corresponding to the query context and a match of a context of said text document with the query context.