There is nothing so practical as a great idea. Putting the sharing economy to work is the Chinese bike-sharing startup ofo. It began life two years ago with its founders pooling private savings of 150,000 yuan ($21,800). CEO Dai Wei, the 26-year-old entrepreneur, named the firm ofo as the letters look like a bike. Its value was recently calculated as more than $3 billion. Over 6 million of the company’s bright yellow bikes can be found in more than 150 Chinese cities, and are now moving into London and Singapore with a planned expansion to 20 countries, including Japan, Spain, France, Netherland, Germany and the Philippines.