The problem I have with abbreviations (why is that such a long word, anyway?) is the same problem I have with poor grammar/spelling.
If people have to read my post twice to be certain what I mean, I've failed to communicate.
When I post something it's because I feel I have something to contribute and the last thing I'd want would be people to not understand what I've written.
Some people might look up the abbrev.
to try to work out what I meant, but if I make people go to extra effort to save myself an extra 10 keystrokes, the time I've saved has been wasted.
Now if the thread is called
Pillars of Eternity and is all about that game, and people quickly switch to only using the PoE acronym, that's fine, because it's clear from the thread title.
But if a thread is
What are your favourite games? and someone includes answers such as PoE, BG, ME, F3 or PoE, KOE that's where it becomes unclear