'It's not easy being green,' moans Muppet Kermit the Frog. For eco-conscious travellers, the difficulty lies in finding a genuinely environmentally friendly hotel. With no internationally recognised standard for green accommodation, travellers have had to make educated guesses as to the credentials of hotels. But that could change with iStayGreen.org - an online social network that works in the same way as TripAdvisor.com, but focuses on environmental factors. Members worldwide are asked to review properties using a green rating system (with the best hotels getting five leaves, rather than stars). Not surprisingly, Hong Kong fares badly; the only five local hotels rated score just one or two leaves.