The "API Basics" PDF doc states that you must a) have an API ID and b) limit your Queries Per Second (QPS) to 7/second.
'b)' sounds like a usage quota to me.
'b)' sounds like a usage quota to me.
If you have an unlimited ride Metro Card, you can use it as many times as you want during the month but you won't be able to swipe it back to back to prevent abuse.
Similarly, 7 queries per second is a decent limit as it allows you to send more than half a million queries (Exact number = 604800 queries) in a day.