SIGDAT was founded in 1993 and is one of ACL's oldest SIGs.
Since its inception, SIGDAT's primary mission has been to organize a series of conferences and workshops, including EMNLP (Conference on Empirical Methods in Natural Language Processing) and WVLC (Workshop on Very Large Corpora). These meetings have become quite popular, and and EMNLP is now typically a 3-day conference with 250-500 attendees and 800-1200 page proceedings.
SIGDAT is generally focused on corpus-based and statistical methods in Natural Language Processing, and encourages initiatives in support of this broader mission from its members.
SIGDAT is the Association for Computational Linguistics special interest group for linguistic data and corpus-based approaches to natural language processing. SIGDAT organizes the EMNLP Conference.