BTSOOM Beats the [stuffing] out of me BTW By the way FWIW For what it's worth FYI For Your Information GR&D Grinning running & ducking IAE In any event IANAL I Am Not A Lawyer, also IANAxxx such as CPA IMO In my opinion IMHO In my humble opinion IMCO In my considered opinion IOW In other words NFW No [bleeping] way NRN No Reply Necessary OTOH On the other hand PITA Pain in the [...] ROF,L Rolling on floor, laughing. RSN Real Soon Now [which may be a long time coming] RTFM Read the [fine] manual (or message) SITD Still in the dark TANSTAAFL There Ain't No Such Than A Free Lunch TIA Thanks In Advance TIC Tongue in cheek TLA Three Letter Abbreviation (such as this) VI Village Idiot WIT Wordsmith in Training WYSIWYG What You See Is What You Get
Also you mentioned A**-hole. The acronym for that body part on this forum is "Clymer".