>>62510
In a strict temporal sense, it's anachronistic on english primary boards. However, it's fundamentally derived from email etiquette (directly) which is the basis of original online BBS culture. As the fag in question I don't care either way; if I was transported back in time or snapped up in space to some alien internet zoo exhibit I'd act just the same way on usenet because it makes sense intuitively to do so, which is really what informs my behavior (where any element of my higher judgement is at play) regardless of whether I'm on heyuri, on some newage hellhole, in some blog's comment section, or actually in a thread of emails.
Realistically, it isn't nu-lingo, it's foreign-lingo. It is literally a usage that was transmitted to me by people who were outside of the sphere of english<-japanese exclusive bbs but which definitely existed and was in use (in that foreign culture) before such a thing ever was. I probably wouldn't use it outside of literal trying-to-appear-new /q/posting like >>62506 unless I was doing something which hinged on some sort of presumed finnish context.