Acronyms have their uses, but even the most dedicated of jargonauts can agree that littering your conversations with them is hardly helpful. Still, over time a significant reservoir of general business acronyms have been added to office lexicons and it can be handy to familiarise yourself with them.
The Muse's Kat Moon has compiled a list of the more common acronyms and even abbreviated, there's still over 120 of them. Moon outlines a number of major areas -- general, finance, technical, marketing and job titles -- which should cover you most of the time.
Some are universally recognised:
COB: Close of business ETA: Estimated time of arrival OOO: Out of office
Others a little less so:
FWIW: For what it's worth IMO: In my opinion KISS: Keep it simple stupid
And a few that I personally have never heard or seen before:
WIIFM: What's in it for me TED: Tell me, explain to me, describe to me