Please give us time to process your requests. If you're sending too many requests too quickly, we'll respond with a 429 error code (TooManyRequests).
You are limited to only 10 requests/sec per account. Practically, this means you must (when possible) authenticate users so that limits are well outside the reach of a given user.
The API response headers also give you the following X-RateLimit value
|X-RateLimit-Reset||1406096275||The Unix timestamp when the rate limit will be reset.|
|X-RateLimit-Limit||10||The rate limit ceiling for your account per sec.|
|X-RateLimit-Remaining||9||The number of requests left for the 1-second window.|