What are some alternatives?
SlideShare - Discover, Share, and Present presentations and infographics with the world’s largest professional content sharing community.
Powtoon - PowToon is a brand new presentation tool that allows you to create animated presentations and cartoon style videos just by dragging and dropping.
authorSTREAM - authorSTREAM enables presenters to upload & share PowerPoint, Keynote & PDF presentations online; embed in blogs, convert to video and share on social networks.
Keynote - Keynote for Mac, iOS, and iCloud lets you make dazzling presentations. Anyone can collaborate — even on a PC. And it’s compatible with Apple Pencil.
emaze - emaze - Online Presentation Software – Create Amazing Presentations
Powerpoint - Explore how PowerPoint can help you tell a powerful story in your presentations and easily share your slides on the web.