THE potential hidden in the informal sector cannot be underestimated. Not just here in Indonesia, but also in other countries. In the Philippines, for example, the total value of unregistered and uncertified slum dwellings reaches US$133 billion. In other words, four times the capitalization of the 216 domestic companies registered on the Philippines' stock exchange. A higher value can be found in Egypt, reaching US$240 billion, or 50 times the va...