>>74
Is it a kind of Japanese acronym?
Honestly, I've never seen it..
I guess I can be of help, if you let me get the context of
how UMA was used, as long as it's Japanese.

And when I wrote the above, something sprung to mind.
Is it "(ﾟДﾟ)ｳﾏｰ"? that you meant?
If so, I can tell you what it's like.

So Uma- often means one's feelings(often a very positive ones),
such as when some food hits the spot, tastes delicious,
or has a good flavour to the extent that you want to shout,
"I love it!", "Very delicious!!" or something like that.
And another meaning is that what's happened is very favorable
to you and you love the situation, so you want to shout,
"It's veeery nice!!", "It couldn't be better!" or what not.
Anyway, both of the usages are slangy, though.

Sorry if I took you wrong.