When he says "ww.com is one of only 24 double letter domain names" I think he's referring to 2 letter domains where both letters are the same. Apparently he's not aware that there are 26 letters in the alphabet.
symbolics.com was registered in 1985
symbolic.com was registered in 1995
Off-topic, but would there be any aftermarket value in symbolics.com? I know the domain is not very exciting, but from a historical perspective is it worth anything?