Emerging text-intensive enterprise applications such as social analytics and semantic search pose new challenges of scalability and usability to Information Extraction (IE) systems. This paper presents SystemT, a declarative IE system that addresses these challenges and has been deployed in a wide range of enterprise applications. SystemT facilitates the development of high quality complex annotators by providing a highly expressive language and an advanced development environment. It also includes a cost-based optimizer and a high-performance, flexible runtime with minimum memory footprint. We present SystemT as a useful resource that is freely available, and as an opportunity to promote research in building scalable and usable IE systems. © 2011 Association for Computational Linguistics.