SubID

In order to track leads on your server the subid parameters are used, they are passed into offers tracking links. In Mgcash there are 3 different subid parameters called sid, sid2 and sid3. In most cases you need only sid parameter to pass so-called "click id" to it and receive it back to your server via the postback process when a lead occurs. These 3 params are mostly equal for Mgcash, but the sid3 parameter is the sub ID parameter that is specifically looking for traffic source values, so if you have different traffic sources, like different affiliates for instance, you need to pass ID of these sources in this parameter.

Example link with all subids specified: http://itrks.com/direct/?cid=366821&uid=1&sid=123&sid2=456&sid3=789