[ATB]

Not to repeat what was said above, but many of us (I suspect) immediately think of THIS when they see someone write "M$" -- http://art.penny-arcade.com/photos/215178115_ExTPi-L-2.jpg

That term simply doesn't come across well in a discussion held - ostensibly - by adults. It has the same effect as someone writing 'MAD LULZ G00G PWNED MS' and ultimately conveys nothing aside from prejudice.

[blasdel]

If you want to use an epithet for the leading operating systems vendor, use Micros~1