Raro is a screen name I've used before GA, and in this sense, it wasn't exactly chosen with GA in mind... but it's got some interesting background.
"Raro" as a pseudonym was used by the composer Robert Schumann (1810-1856) ... to quote encyclopedia.com,
In order to observe music from all points of view, Schumann invented three artistic characters: the stormy, impetuous Florestan; the gentle, lyrical Eusebius; and the arbiter between the two, Master Raro. In later years Schumann signed many of his own compositions with these appellations.
Further comments, via Google Books:
Raro was the most delicate of the "Davidsbundler" [schumann's imaginary personas]. He was in his irony, which had drunk deep of worldly wisdom, raised far above the storm and stress of Florestan and the gentle, simple complaisance of Eusebius. In Florestan there was much of Beethoven, in Eusebius an echo of Schubert. Raro was to surpass and combine them in a higher unity. But Raro is just---rare.
On that note, "raro" is also a Spanish (which I don't speak) word meaning something like "rare".... Dictionaries more thoroughly translate it as "bizarre, queer, rare, unusual, eccentric..."
Does that explain it?
-- Master Raro