Everybody is talking about Uber's announcement, but Sidecar is also apparently experimenting with the same thing:

http://techcrunch.com/2014/06/29/sidecar-shareable-rides/

There are also many ways to grow the product: for example, I know that Uber will be getting into local package delivery before too long. It looks like Lyft/Sidecar/Hitch/Flywheel are keeping them on their toes in the meantime.

One thing is certain: there is cutthroat competition in this industry that will only benefit the consumers.