My client is using YQL with the public interface.
"http://query.yahooapis.com/v1/public/yql?q=select * from geo.placefinder ..... etc"
Some of the documentation says that the number of hits is 2000 per hour, and other documentation says that it is nearer to 2000 per day.
Which is it?
YQL tables for development
If you are looking to continue experimenting with the standalone PlaceFinder and PlaceMaker services, we are excited to continue supporting you through our YQL tables. These tables will be limited to 2,000 queries per day and are meant for non-commercial usage. We intend to shut down the current free versions of PlaceFinder and PlaceMaker on November 17, 2012.
Or this, from the FAQ?
How many times can I call YQL in a minute/hour/day?
Rate limits in YQL are based on your authentication. If you use IP-based authentication, then you are limited to 2,000 calls/hour/IP to the public YQL Web service URL (/v1/public/) or 20,000 calls/hour/IP to the private YQL Web service URL (/v1/yql/) that requires OAuth authorization. See the YQL Web Service URLsfor the public and private URLs. Applications (identified by an Access Key) are limited to 100,000 calls/day/key*. However, in order to make sure the service is available for everyone we ask that you don't call YQL more than 0.2 times/second or 1,000 times/hour for IP authenticated users and 2.7 times/second or 10,000 times/hour.
YQL is an independent web-service which serves Yahoo/Non-Yahoo Tables. It Imposes own limit of on its service URL on all the tables , which is IP based restriction to avoid Denial of Service attacks.
Read about its limit here
Note: API key owners have different API limit on YQL.