A data mashup system having information extraction capabilities for receiving multiple streams of textual data, at least one of which contains unstructured textual data. A repository stores annotators that describe how to analyze the streams of textual data for specified unstructured data components. The annotators are applied to the data streams to identify and extract the specified data components according to the annotators. The extracted data components are tagged to generate structured data components and the specified unstructured data components in the input data streams are replaced with the tagged data components. The system then combines the tagged data from the multiple streams to form a mashup output data stream.