Write quota
From Freebase
Each user has a (very high) daily write limit. Default quotas on the production server are 10,000 writes per day. Default quotas on the sandbox quota are 1,000,000 writes a day (not really unlimited, but probably more than you can burn through in 24 hours from a remote connection).
Users with non-default quotas have the *same quota* on both production and sandbox servers (i.e. it propagates every week). The error message is "/api/status/error/mql/access Too many writes."
This app shows you how much of your write quota you've used in the last 24 hours as well as breaking it down by 4 hour chunks so that you can see when you'll be getting more if you exhaust your quota. You can take your user id on the URL as a parameter to get someone else's .
The read quota is 100,000. This works out to 1.15 queries a second, all day.