You never HAVE to use it. It is appropriate when you are stating a personal opinion about something that others may not agree with, or that you can't really back up with facts. To a certain extent it is acknowledging that the opinion is definitely biased and will come across as arrogant.
Examples:
There may be some facts that could support those view points, but the reality is that it is a matter of personal preference and opinions are going to vary. And most people tend to use IMHO instead.
IMAO stands for In My Arrogant Opinion.
In My Arrogant Opinion.
lmao stands for Laughing My profane Off
Dead or, I'm so tired, im going to go to sleep now. In general, something that no one really cares about. IMAO, the worst FB status is I'M QUITTING FACEBOOK!!!!...yeah. You see?
They must be smart girls
IMAO stands for In My Arrogant Opinion.
Kyle Imao's birth name is Kyle Adrian P. Imao.
IMAO stands for In My Arrogant Opinion.
Keinen. Imao has written: 'Jingnian hua niao hua pu ='
Kyle Imao was born on October 5, 1999, in Marikina City, Philippines.
No.
in my arrogant opinion
in my arrogant opinion
imao
In My Arrogant Opinion
Painter
In Internet slang, it can stand for "In My Arrogant Opinion". Unless you mean "LMAO" Which would be "Laughing My ass Off"