"IIRC" is an acronym that is short for "if I recall correctly" and is used in online conversations or email. It is used when answering a question from a position of being unsure about the validity of the statement or topic.
"IIRC" is part of a growing list of slang acronyms that began development with the introduction of the Internet. Shorthand and acronyms were developed to ease communication speed on the Internet. Other forms of Internet slang include emoticons and words that have changed in meaning. Another form of Internet slang involves phonetic transcriptions of foreign words to create a new word. An example of this is the usage of the word "impossibru," which is derived from "impossible."