The 'Compulink Information eXchange'.
Similar to the old bulletin boards, but vastly different in some ways, most noticable the common use of an off-line reader to view new messages.
To those who know of it, CIX is considered to be one of the great ways of gathering information as is is almost certain that there will be someone using the system who will know something about any subject you choose.
At any given time you will find people bickering (the main form of communication) on subjects as diverse as 'whether Julius Caesar really conquered the UK' and 'the best way to write a book accurately set in the Middle Ages'.
Those who use the system are known as Cixen