There are differences among these three use cases for entity extraction:
- Operatives reviewing content for information about watched entities prior to an operation
- Identifying people, places, and things for a marketing analysis by a PowerPoint ranger
- Indexing Web content to add concepts to keyword indexing.
Regardless of your experience with software which identifies “proper nouns,” events, meaningful digits like license plate numbers, organizations, people, and locations (accepted and colloquial)—you will find the information in “Performance Comparison of 10 Linguistic APIs for Entity Recognition” thought provoking. The write up identifies the systems which perform the best and the worst.