I have gone through many profiles on Nairaland and it is amusing what people write on the column for YIM.
You would see things like:
"What does that mean?"

"Meaning"

Some even put write up there or put their blog add.

I don't it's much of a big deal not knowing the meaning of YIam, considering it almost outdated.
Back in the days YIM and MSM were the popular means of social media communication and it simply means:

YIM: Yahoo Instant Messenger
MSM: MicroSoft Messenger

Now that you know, what do you think?