Each member has put forward equity/taken a stake in the shopping mall and participate on even more levels. Since T-ara Dot Com has only recently opened, it generates a revenue 30 million won per day and is taking its first steps as a successful internet shopping mall.
If they're taking some stake [in the company] then they're probably getting something back from the revenue.
Or perhaps when T-ara Dot Com is closed down for some reason, they'll probably get some percentage each.
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Source: http://news.naver.com/main/read.nhn?mode=L...;aid=0000185677
CR: Newsen, oniontaker (translations), IDUNLAIKSPAMMERS (information)