Rama Lakshmi: India encourages emigrants to invest in their homeland, offering dual citizenship to the Indian diaspora in the United States, Britain, Canada, Australia, New Zealand and Singapore (sort of the Anglosphere, what?). Indians have noted that "The Chinese diaspora contributes almost 60 percent of China's total foreign investment, while Indians abroad contribute 4 percent of India's foreign investment." (Not that the Chinese get dual citizenship. This is the kind of thing that Jagdish Bhagwati also advocates for poor countries generally.

The Economist also recently had something about how emigrants could influence their home countries. But it's not always to the good. Eritrea taxed the personal income of its citizens abroad to help finance its stupid war with Ethiopia. (Note that Bhagwati also suggests taxing �migr�s.) Similarly, Tamil exiles supported the Tamil Tigers against the government of Sri Lanka. And in the 1970s and 1980s, Irish-Americans raised huge amounts of money for republican terrorist groups such as the IRA.

update
Amy Waldman: "foreign direct investment by Indians abroad is only $1 billion, compared with about $60 billion invested by 55 million overseas Chinese."