What is Courtesy limit for Google's API?

Any one can tell me what means "Courtesy limit", such as like 1000 queries / day, for Google's API?

If I am using some Google APIs in my app and give the app to users, does that "1000 requests / day Courtesy limit" apply to each user or to the overall?

I mean, if 10 users are开发者_运维问答 using my app, so does each of the users can have 1000 requests / day, or each of them can have just 1000/10 = 100 requests / day?

Thanks

The courtesy limit is against the account/API key you are using - as each use of your application uses your API key, this courtesy limit is your and you are sharing it with your users. This means the total limit is 1000, divided amongst all your users.

edit: There is a useful API Dashboard for paid APIs