MoneyBackCo stands for MoneyBack Community, founded by Steve in 2007 to provide cashback/moneyback from online retailers via affiliation network. Excerpt from their website:

What is it?

MoneyBackCo is the original Australian 100% moneyback/cashback website, where the consumer is in control. Instead of losing all or a vast majority of referral money that online businesses pay to attract customers to their website, you get to know exactly what the companies are offering referrers and the best bit is you get that back rather than someone else, and you receive 100% (after a $10 membership fee has been deducted from your earnings).

MoneyBackCo charges its members up to $10/year subscription fee (from the moneyback they made).

In March 2007, OzBargain has announced its partnership with MoneyBackCo. Basically for every deal posted on OzBargain, it will query MoneyBackCo whether this merchant has been featured (based on the URL), and then provide a link to MoneyBackCo with the moneyback amount, if members can get more discount via moneyback.