I thought I was pretty 'Net savvy, but this is a new one.
At first I thought it was a drumroll, or cymbals, like after a joke. But it’s used in place where nothing is funny.
I’ve asked occasionally but no one answers me. Come on, 'fess up. I know the secret about Cecil now, I’ve got over 600 posts, I’m part of the group! Please tell!
bamf
X-Men reference. It’s the sound-effect of Nightcrawler’s teleportation.
You’re not alone. I have no idea what it means either.
To clarify, people use it to finish their posts, as if to give you the visual of them having spoken about something, then teleporting away in the manner of Nightcrawler.
It’s a neat bit of comic-inspired onomatopoeia, actually - ‘bamfing’ having become synonymous, in some circles, with ‘teleporting’.
The origin is the X-Men comics, not the movies. From an era when comics included cheesy, odd sound effects.
The sound of Wolverine’s claws being extended, for instance, is ‘snikt’.
This is correct. It is ‘snikt’, and ONLY ‘snikt’. All who would attempt to use a cheesy B-movie metal-against-metal “schiiiiiiinnnnng” must answer to the very claws they desecrate. Even though the metal-on-metal probably makes more sense, since it’s adamantium sliding across adamatium. I don’t care. The sound is ‘snikt’.
bamf
You mean they don’t do this anymore! 
No, sadly, sometime along the path to the grittier, more realistic comics of today, the sound-effects fell discarded by the wayside, relegated to use only in humorous books. Oh, sure, you’ll still see one sometimes, but not very often.
Also, on props associated with Samuel L. Jackson, i.e. his lightsaber in the Star Wars prequels (though you can’t se ti) and on the wallet in Pulp Fiction.
It stands for:
Bad-ss Motherfcker 
Ok I get it now. It’s kind of silly though, I mean teleporting away after a post? Why? What’s the point?
It’s just a kind of reference. If I ended every post with “And that’s the way it is.” - am I trying to assert that all of the preceding was indisputable fact? Heck, no. It’s just that I’m making reference to Cronkite’s famous news sign-off. Maybe I’m a Cronkite fan (a Cronkiteite?), or the like - the reference means something to me, but not necessarily to the audience.
I’ve seen the bamf thing only with one poster that I specifically recall - Shirt Ninja 13 - I believe that’s the tag - and in that case, I can see the “bamf” being extending to the classic Ninja disappearing act - IE , throwing down a smoke bomb and disappearing.
Oh, I’m not saying people shouldn’t do it, if they feel like.
I just think it’s silly. But at least the Ninja thing I can see.
Well, I was just trying to answer the ‘Why’ question there.
Thank you, I appreciate that. 
I allus thunk that Bamf was a city in Canada, near Calgary, all fulla mountains and skis and such…?
Hey, stop by us indie comics some time, we still use them!
Close, but no cigar, Dex–it’s Banff, Calgary.
Kythereia, I’m afraid someone will now have to explain “whooshed” to you.
…I knew it.
You know what’s funny? After writing all this today, I pick up my comics this evening, and look at the new Conan One-Shot - and it’s got the silly sound effects!
Pfft. Everything old is new again. Whipper-snappers.
Poor dear. :: pats Kythereia on the shoulder::
One thing I love about the Straight Dope is that I hardly ever have to ask my own question. If I wait long enough, some intrepid Doper asks for me.