He’s now back, with his old claim of having invented e-mail in 1978. He even got the Washington Post and Time to do stories about him, and gave his documents to the Smithsonian.
So I suppose the people who wrote RFC 561 were five years ahead of their time — recommending standards, in 1973, for a medium that was not invented until 1978. In fact, Ayyadurai should pick his next fight with Ray Tomlinson who claims to have sent the first network email in 1971. And when Eric Allman wrote delivermail (which evolved into the ubiquitous sendmail) in 1979, he must have been ripping off Ayyadurai.