The beautiful part has been cropped, but the beastly part thanks you just the same.
Sock puppet is a handy word. Sometimes I refer to my youngest by that, a term of endearment, of course.
I don't think I've used more than a dozen handles in more than 20 years - and I couldn't begin to guess how many fora; however, in most fora it has been some variation on "Zdim", "TheFiend", or "TheFallibleFiend." Zdim was the main character in L. Sprague deCamp's book, "The Fallible Fiend." (Not recommended, unless you're into hack science fiction) Generally I don't use more than one handle on a given forum. (Three exceptions: on Undernet one can't reserve handles and sometimes someone takes "TheFiend", on bitnet relays I used several different handles to suit my mood but most everyone knew who I was - no attempt to hide, in another case I wanted to say my piece and avoid potential stalkers.)
In most circumstances I think it's a little tacky. I'm not aware of any formal etiquette rules regarding handles, but this just seems like something an adolescent would do - like putting blatant profanity in one's handle.
There are not a lot of rules regarding handles in general, though many specific fora have rules regarding names. For example, my handle is not permitted on xian irc channels. If I show up, they will either boot me or ask me to change my nick. I leave.
It's considered - or at least it used to be considered - a serious taboo to publicly criticize someone's handle, even though some handles were generally considered tacky:
usually, blatant profanity was frowned on, although clever innuendo earned respect
k3wlsp3@k was a sure way to identify yourself as a child
whiny, fake-noble names like betrayedyettrusting or pornsurvivor earned eyerolls
religious themes were good, but not proselytizing: so JesusFreak might be acceptable, but HeIsRisen would seem too much like an advertisement.
No matter how stupid a handle, though, it was just considered bad form to comment negatively on them publicly. We might roll our eyes. We might even killfile (not me, but some did). But we generally said nothing about stupid handles. OTOH, it was always fine form to comment on an especially interesting or good handle.
I'm not aware that this was written down anywhere. We just didn't do it. Well, some very few did, but they were generally ignored. My memory is not perfect, of course. Perhaps I am expressing nostalgia for the good old days that never were. But that's the way I remember it.
Anyway, back to the point, other words for handle. I've seen some very few cases where people used the word avatar instead of handle. This is clearly an incorrect usage, BUT I would include it if it were a common misusage. Persona is one. Though usually that refers to the personality behind a handle, it's sometimes used loosely to mean the handle itself. I'm not sure how common that usage is, though.
