18. The computing system of claim 17 wherein the processor is further configured to, while executing the aggregation service: transform entity types of annotations in the extraction results from service-specific entity type schema to a standardized entity type schema; identify and mark relevant annotations among the annotations in the extraction results; identify annotation areas in documents; and use an aggregation approach to identify an aggregated set of annotations for the extraction results.
18. The computing system of claim 17 wherein the processor is further configured to, while executing the aggregation service: transform entity types of annotations in the extraction results from service-specific entity type schema to a standardized entity type schema; identify and mark relevant annotations among the annotations in the extraction results; identify annotation areas in documents; and use an aggregation approach to identify an aggregated set of annotations for the extraction results. 19. The computing system of claim 18 wherein the aggregation approach uses one or more of extended majority vote analysis, weighted majority vote analysis, simple error path analysis and pairwise error path analysis.