ISO (Insurance Service Office) that writes most industry standard coverage forms, which are adopts by most insurance companies has changed language that may be affect auto insurance policies where insureds are using their cars to participate in ride sharing programs like Uber and Lyft.
The new language may exlcude coverage for medical payments, uninsured motorist, and damage to your auto if the vehicle is being used to convey people from the general public for a fee or donation.
If this exclusion is applied, and one of your passengers is injured during an accident, there may be no coverage under your auto policy for bodily injuries. It may also void damage to your vehicle as well. I believe the exclusion being applied is for Individuals making their auto available for "public transportation" like a commercial vehicle or taxi.
I don't believe this exclusion would apply to individuals who take turns carpooling with friends, or transports fellow employees on a regular basis. You can argue that their is no difference between carpooling friends or complete strangers like Uber and Lyft, but the courts will probably have to make the final determination.