Yes, you can add &subid=XXXXXX to your links to track quality of your sources.
To use this option properly, please, make sure your link looks like this:
​http://in.tubecorporate.com/in/tcc/?promo=12345&mc=89012345&dc=88812345&tc=88912345&subid=XXXXXX
​
By going to Popunders -> Statistics -> Sub IDs in your TubeCorporate admin panel, you'll see productivity of your sources.
You can sort data by Productivity and get a list of Sub IDs which affect your eCPM in a negative way.
​
​NOTE: Productivity is based on a ratio of Clicks to Unique Visits, so the smaller is the percentage of productivity of a source - the worse is a quality of its traffic.