The Series D round of funding apparently values the business at $1.2 billion (£780 million). That means that BlaBlaCar is now a European "unicorn" (a startup valued above $1 billion).

TechCrunch reports that BlaBlaCar's Series D round will be led by Insight Venture Partners, but with participation from business angels.

BlaBlaCar confirmed to Business Insider that its founders are speaking with investors, but the company did not confirm any of the funding details reported by TechCrunch.

BlaBlaCar doesn't work like other ride-sharing services. It's designed for longer trips between cities, not for travel within them.

Riders book trips between cities and destinations in advance with drivers who already traveling the route. Customers pay a small fee for the journey, and BlaBlaCar takes around a 10% cut of the price. There's also a system that controls how much you want to talk to your driver. Select "bla" if you're not feeling talkative, but you can also choose "bla bla" if you're a little chatty, or "bla bla bla" if you're keen to make conversation.