IIRC is frequently used to convey a memory or fact with some degree of ambiguity in casual online discussions.  It frequently appears in online forums, gaming chats, Reddit threads, comment sections, and text messages.  One could add, for example, "IIRC, she worked on that project too."  The use of a cautious tone conveys the speaker's desire to participate even while they are unsure.  There are many other meaning of IIRC, but this is the most commonly used. Know more about what does iirc mean