Draftsend - Presentations you can 👀 and 👂
Zeetings - Turn your presentations into interactive conversations
Reveal.js - A framework for easily creating beautiful presentations using HTML
Crowd Mics - Crowd Mics provides solutions to turn phones into microphones for live events to boost audience interaction.
Slidebean - Presentations that design themselves
SlideShare - Discover, Share, and Present presentations and infographics with the world’s largest professional content sharing community.