A description of ACM is as follows below (taken from http://www.acm.org/about/fact_sheet ):
"About ACM: ACM is an educational and scientific society uniting the world's computing educators, researchers and professionals to inspire dialogue, share resources and address the field's challenges. ACM strengthens the profession's collective voice through strong leadership, promotion of the highest standards, and recognition of technical excellence. ACM supports the professional growth of its members by providing opportunities for life-long learning, career development, and professional networking.
Activities: ACM carries out its mission through conferences, publications, educational programs, public awareness activities, and special interest groups. It sponsors over 170 conferences annually, including conferences on computer graphics (SIGGRAPH); data communications (SIGCOMM); mobile computing (SIGMOBILE); knowledge discovery and data mining (KDD); software engineering (SIGSOFT); high performance computing (SC); human computer interaction (SIGCHI); object-oriented programming (OOPSLA); and freedom and privacy (CFP)."
Emails may also be sent to: email@example.com