ICYMI (in case you missed it) and IYKYK (if you know, you know) which frequently get crossed in my head

PCMCIA but we don't need to use it much nowadays

FLOSS; only because I can only pronounce the second word as leeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeber.

What, no votes for 'goatse'?

I'll uh show myself to the logout button now

One that always confuses me is MSM. For over 40 years it has been used to mean "Men who have sex with men", but recently conservatives started using it to mean "mainstream media" and its sometimes hard to tell which of their hates they are talking about. MSM is still widely used in the medical community when discussing/classifying patients and in the ongoing AIDS epidemic.

Either FR or PFP. "FR" just feels like another filler word. PFP... I'm too used to calling them "avatars", it just feels wrong and superfluous. I'm probably aging myself here.