Last week’s Economist published a map of the world’s top 20 destinations for Chinese and Indian migrants. Did you know that there are more Chinese people who live outside mainlandChina than French people in France? If migrants were a nation, they would be the world’s fifth-largest, which means a little larger than Brazil. The ease of staying in touch with those at home is making this group of migrants matter much more. There isn’t any other social network with the same influence and some firms are taking notice.

The diaspora networks have three lucrative virtues. First, they speed the flow of information across borders. Second, they foster trust. Third, and most important, they create connections that help people with good ideas collaborate with each other, both within and across ethnicities.

Migrants to rich countries not only send cash to their families; they also help companies in their host country operate in their home country. A Harvard Business School study shows that American companies that employ many ethnic Chinese people find it much easier to set up in China without a joint venture with a local firm.