I've maintained for some time that what we need is a sticky (no! not another one!) of frequently-used acronyms. Because, frankly, there are some that aren't going to get spelled out in every post as Mugaliens suggests. "ATM"? Even though we all use it in at least two contexts, even just around here, we will continue to expect people to know when we mean "Against the Mainstream" or "Automatic Teller Machine."
Now, I don't use "IIRC." Or even "BTW," much. "AFAIK"? Not a chance. But I don't think we're ever going to stop people from using them without spelling them out in advance, and with common ones--and, you know, "BH" is one of them, at least around here--I don't think we should have to. I'm perfectly willing to work on the list. If we ever get a board wiki up, as some other boards have, I'd even put in the effort to keep it in alphabetical order, which it really should be. There are even a few threads buried around here with board-specific acronyms; I think I started one myself. But this is the world the internet has created for us, I'm afraid. That's why I think a sticky would help--stickies are the tools boards use to provide needed information, and a glossary would often help.
"Now everyone was giving her that kind of look UFOlogists get when they suddenly say, 'Hey, if you shade your eyes you can see it is just a flock of geese after all.'"
"You can't erase icing."
"I can't believe it doesn't work! I found it on the internet, man!"