Earlier there was a karma function where you could "nuzzle" or "bite" someone. If you were bitten, you'd get minus points. This was removed a few months back.
The Floof-O-Meter is when you've (as above have said) got +25 posts counted on the forum. You can see how many posts you've made above your profile picture.
If you get the help you need from an user, or if it's simply someone you like/recognize from before, you can choose to nuzzle them and therefore give them +Floof.
I hope this cleared things up a little. ^^