Significance of cache buster in click tracker

Cache buster mostly used in impression tracker provided by third party.In order to understand its role, we need to know its functionalities.Cache-busting is a dynamic generated code that prevents a browser from reusing an ad that has already been viewed and stored in the user’s temporary web browser files. 

Cache buster is %n which on each impression generate unique value. Also it burst the cache present on the system.The random number makes every ad call look unique to the browser and therefore prevents it from associating the tag with a cached file, forcing a new call to the ad server.

• Example:

<SCRIPT SRC="http://xxxx.adnxs.com/xxxx?id=xxxxxx&cb=[CACHEBUSTER]&pubclick=%%CLICKTAG%%" TYPE="text/javascript"></SCRIPT>

Now in case of click tracker, %c is used as macros but there are third party which take  precautionary measure to verify the clicks recorded.

So if third party click tracker have placeholder for the cache macros
then append %n.So when user clicks, unique value will be generated which will be recoreded by third party  ad server.Each click made by user in this session will be recorded but only single click will be count as valid.This methodology will insure that click fraud will not happen.

Click fraud is when a web site either clicks on its own ads to increase revenue, gets someone else to click on them with no intention of buying or works with botnets to generate millions of illegal clicks.


For some adserver cache buster in click tracker play very vital role.

In such kind of server if below is 
Impression tracker

http://adserver.com/ads/impression/tracker/imp=%n

Click tracker
http://adserver.com/ads/clicks/tracker/imp=%n

In this case when %n is replaced with unique number and user click on the creative then unique number will be generated for %n present in click tracker also.

Impression will be counted only when these number (%n value from impression tracker and %n value from click tracker) is same then only impression count will be increamented.

To Know more about cahce buster please refer 
http://adtagmacros.blogspot.com/2014/10/cache-buster-and-click-macros.html