I see a lot of abbreviations & acronyms on here - what do they mean?

Sites like abbreviations.com, thefreedictionary.com, webopedia.com & urbandictionary.com may all be of use for this.
 

There is also an OT•com ‘acronym buster’ guide, here:-
 

Please note: whilst some abbreviations / acronyms may make it a lot easier / quicker to type or read certain word & meanings - the use of ‘txt spk’ on here is not encouraged - so please refrain from using it, thank you.