Google clearly explains that :
Use of the Google Geocoding API is subject to a query limit of 2,500 geolocation requests per day. (User of Google Maps API for Business may perform up to 100,000 requests per day.) This limit is enforced to prevent abuse and/or repurposing of the Geocoding API, and this limit may be changed in the future without notice. Additionally, we enforce a request rate limit to prevent abuse of the service. If you exceed the 24-hour limit or otherwise abuse the service, the Geocoding API may stop working for you temporarily. If you continue to exceed this limit, your access to the Geocoding API may be blocked.
Let say i call it as client side
<script type="text/javascript" src="http://maps.googleapis.com/maps/api/geocode/json"></script>
and I call it as serverside
<?php
$mapdata = file_get_contents('http://maps.googleapis.com/maps/api/geocode/json');
?>
What is the difference in query limit count?
This means what? I am not clear here. Per day it will count per domain or server ip or client ip?
If your code is running client side, then they will use the requesting client IP, if your code is server side, they will use the server request IP.
In other words: If you are making your requests from your server, you will be more likely to hit that limit if you are not cacheing the results.
What you need to watch out for is the request rate limit – if you make too many requests within a very short amount of time, they block you.