It's a 100% horrible idea. To undertake it shows unworldliness and poor judgement. It's all alright until it's not - and there are plenty of examples of shoddy aviation pseudo charter operations bringing grief and misery the world over.
I've been a private pilot and aircraft owner for 35 years, doing all I can to stay sharp and current. But I refuse to do cost-shares even with business colleagues on work trips. The way I see it, partly based on judgements flowing from some of the many tragic events written up in many jurisdictions, it'd be almost impossible to (i) defend myself from the charge that I was offering a commercial service, minus many of the safeguards that entails and, more importantly, (ii) convince myself that I was not so doing.
Incidentally, I do use both Uber and AirBnB and feel both are useful, but over-hyped. I've occasionally refused offered services on both of them, citing safety or suitability concerns. To put it in perspective a little, I've also insisted on a change of aircraft during work commercial charters. Judgement is a sizeable component of all aviation.