From the Business Insider excerpting policy:
We excerpt others the way we hope others will excerpt us.
What does that mean? It means that if you think our stuff is worth bringing to your readers’ attention, we are honored and grateful. Please excerpt it as liberally as you want. In return, please just give us clear credit, links back, and an incentive for interested readers to visit our site. (Not all readers–some.)
This is an issue I agonise over a fair bit, and it’s interesting to learn that BI are actually somewhat more permissive in this area than I would expect them to be.