Here are some: holiday companies charging extra during school holidays; effects of welfare reform on sick and disabled people; stopping female genital mutilation in the U.K.; cervical cancer screening tests and the case of Sophie Jones; making Eid and Diwali public holidays; research funding and awareness of pancreatic cancer; ending the conflict in Palestine.
Many of those things, if not all of them, are extremely important. Without e-petitions, would they have gone unnoticed by the House of Commons? I'm fairly sure that at some stage in our parliamentary life they would have received a debate. Did e-petitions make sure that the debate happened earlier? Possibly they did.