Is MQUOTE a new button,as I don't recall it being there all along. I meant to ask this for a week or two.
And what does it do?

That button used to say "+Reply".

It had to be changed as it is actually used to pick up multiple quotes from several posts in the thread to use in a reply.
If one picks several posts to quote, you click on that button in each post to add to your reply.

It was confusing to some when what they really wanted was the "Reply" button at the very bottom of the thread.

I liked it better when the "quote" button would turn red and then after you got about 3 of them (or how many of them you wanted) you could then click "add reply."

Yano,
It still works the same way as before - only the button name was changed.

Hey thanks to both of you. I knew it was something,just couldn't remember. I did click it and had it glowing red, But I shut it down thought I was nuking something. Well at least saved a trip to the shrink

Ah yes, KY. I must be thinking of another forum.