Sometimes I swear that people are just making up acronyms here to troll people.
I assume you mean "orders of magnitude" and not "out of memory". I have never seen the former used as an acronym before, let alone without some kind of contextual clue. (In typical Baader-Meinhof fashion, I'm sure I'll see it again in the next 24 hours...)
Nailed it!
https://news.ycombinator.com/item?id=48001905