The ARPANET computer network made a large contribution to the development of e-mail. There is one report that indicates experimental inter-system e-mail transfers began shortly after its creation in 1969.
Ray Tomlinson (akong sangay) is credited by some as having sent the first email, initiating the use of the "@" sign to separate the names of the user and the user's machine in 1971, when he sent a message from one Digital Equipment Corporation DEC-10 computer to another DEC-10. The two machines were placed next to each other. The ARPANET significantly increased the popularity of e-mail, and it became the killer app of the ARPANET.
Most other networks had their own email protocols and address formats; as the influence of the ARPANET and later the Internet grew, central sites often hosted email gateways that passed mail between the Internet and these other networks. Internet email addressing is still complicated by the need to handle mail destined for these older networks. Some well-known examples of these were UUCP (mostly Unix computers), BITNET (mostly IBM and VAX mainframes at universities), FidoNet (personal computers), DECNET (various networks) and CSNet a forerunner of NSFNet.
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