Here’s some more evidence that the sharing economy is becoming a significant trend in social commerce. AirBnB, the user-review-powered P2P marketplace that allows people to share their homes with travellers around the globe has just joined the billion dollar valuation club, following a new $112m round of investment and valuing the 36 month old startup at $1.3bn.

With 2m bookings in 16,701 locations across 186 countries, a neat escrow system to take the anxiety out of private B&B bookings, and a domestic lodging market worth $125bn, AirBnB is looking to expand through Europe and Brazil.  Why on Earth eBay or big travel brands didn’t give birth to AirBnB is a mystery. Elephants can’t dance and all that – which is good news for social commerce startups. Checkout the GigaOM video with AirBnB CEO Brian Chesky embedded below.

So here’s a brainstorming question.  What would be the AirBnB of your industry? If it’s going to come, you might as well own it.