If you follow FICO scores please search threads about AZEO (All Zero's Except One) which is referenced to maximize some scores which is what @Anonymous is referencing. As noted above, there is a penalty for All Zero's as the formula assumes you're not using your revolving credit and can't determine your responsibility of paying (no memory, just raw #'s at time reported). It's just part of the algorithm and one of the many things communicated and learned here.
As @Anonymous says, report a balance on 1 major bankcard, it can be as low as $5. Let it report on your statement which will report to the CB's for most cards, pay before the due date and no interest charged. That's enough to satisfy the FICO algorithm Gods. It is what it is, regardless of how much sense it makes to some. But that's if you're focused on scores.
Your OP mentions myKarma and I assume you meant Credit Karma instead of MyFICO because there is no myKarma. Those are not FICO scores. You may see what you expect to see with Credit Karma but may be surprised if you app something and get different scores because most (90+%) of lenders use FICO scores.
