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In the United States especially, most media monitoring services capture and index closed captioning text from news and public affairs programs, allowing them to search the text for client references. The use of closed captioning for television news monitoring was pioneered in 1993 by Tulsa-based NewsTrak of Oklahoma (later known as Broadcast News of Mid-America, acquired by video news release pioneer Medialink Worldwide Incorporated in 1997). US patent 7,009,657 describes a "method and system for the automatic collection and conditioning of closed caption text originating from multiple geographic locations" as used by news monitoring services.