I was looking for a tool that shows seat availability on flights so I can estimate my chances of getting bumped on a flight (or getting on as a standby). I did a search for "seat avail" and one of the links was KVS. Before I invest in downloading and learning how to use KVS, I like a brief summary of what it can do. A summary by the moderator as a "sticky" at the begining of this thread would be great. It would cut down silly questions such as mine.

Things I want to know:
Does it work world wide or just certain countries?
Is it suitable for USA only searches.
Would it fit the requirements I mentioned above?