Decades ago, Bradley Jacobs studied math and piano (classical and jazz) at Bennington and Brown before dropping out to make money. Now the balding 61-year-old CEO of XPO Logistics invokes that background to explain how he's parlayed sequential roll-ups in the gritty businesses of garbage collection, heavy equipment rentals and delivering stuff into a $2.6bn net worth.

Selling apparel and other merchandise over the internet is difficult enough for retailers as it is. Now they want to make it even tougher on themselves.

How do you tell if your supply-chain partners are financially solvent? The crowd knows.