My own opinion
MOO is that Yamaha keyboards sound better than similar Korg models.
|IMHO||In my honest opinion|
|IMAO||In my arrogant opinion|
|IMBO||In my biased opinion|
|FTR||For the record|
|FWIW||For what it's worth|
MOO is a quick way to preface that the following or preceding opinion is your own. It is similar to IMO but is less common, probably because it looks like the sound a cow makes.
There are many times in which you might use MOO, primarily online in messages, forums, and social media. For example, your friend may send you a pic of her in her new dress, and you might message her, "MOO, that new dress makes you look like a cow."
Since MOO is the same as the sound a cow utters (not udders), you might confuse the recipient if they are not slang-savvy. Therefore, use MOO with discretion.