I know I can't. I don't even try. I did come across
this list of chat acronyms and a very nice explanation of how to use these acronyms and how not to use them. There is even a great set of warnings:
- Never use an acronym unless you are sure of its meaning, because if you say the wrong thing to the wrong person.....
- Try not to use chat acronyms in real life, especially in formal writing or conversation. Doing this could be embarrassing depending on who you're communicating with.

Good stuff. This list appears geared towards text messaging, but I imagine there are a few others on there that most people here might use every day in forum life.
Some of my favorite examples:
- BBFD: big bad forum discussion <-- huh? Never heard of it!
- CID: crying in disgrace <-- for the emos
- GFY: go f*** yourself/good for you <-- make sure you don't get these mixed up!
- GYPO: get your pants off <-- I can imagine two people in bed, both of them furiously texting each other before intimacy... yeah.
- IMNECTHO: in my not-even-close-to-humble opinion <-- who the hell would get this one?!?
- IPN: I’m posting naked <-- because I usually do
- OMGBBQWTF: oh my God, Bar-b-q, What The F*** (surprise and confusion) <-- huh?
- OP: original post/original poster <-- is that like Original Gangsta?
And my absolute favorite!
- Pwn: to triumph (not actually an acronym, but rather a misspelling of own)
