First of all, we don't keep score. :)
It's
rather the same process as in a real game, except the
questions are posed a few words at a time. You type "buzz"
or the equivalent to buzz in. The one major
difference is that, if you weren't the first person to buzz
in at a given point, you can "unbuzz" (especially if
the first person gave the answer you were about to
give :).
As far as "clearing" goes, Y! does not
let you post the same thing twice in a row.
Therefore, you need to 'clear' your buzzer by (a) using a
different phrase each time, or (b) typing in something
other than the phrase you use to buzz.
--STI